Recording medium, recording apparatus and recording method

ABSTRACT

Optimum movement of first and last signal pulses based on the data pattern is determined before data recording to record marks in the correct position. A specific pattern signal is read from a disc track and digitized with an appropriate slice level by the digitizing circuit ( 115 ). A pulse position offset measuring circuit ( 120 ) then measures specific edge intervals in the resulting digital signal. Movement of the first and last pulse by the pulse moving circuit ( 110 ) is then set so that the offset between the measured edge interval and a predetermined standard edge interval is ideally zero.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a data recording medium, a recordingapparatus and to a recording method for recording information to thisdata recording medium.

2. Description of Related Art

Data recording devices for optically recording information, andparticularly digital data, to a storage medium are commonly used as aconvenient means of mass data storage.

Phase change optical discs are one type of optical data recordingmedium. To record to a phase change optical disc a semiconductor laseremits an optical beam to a spinning disc to heat and melt a recordingfilm on the disc. The achieved temperature and the cooling process(rate) of the molten film can be regulated by controlling the power ofthe laser beam, thereby inducing a phase change in the recording film.

When laser power is high, the recording film cools rapidly from a hightemperature state and thus becomes amorphous. When a relatively lowpower laser beam is emitted, the recording film cools gradually from amedium high temperature state, and thus crystallizes. The resultingamorphous parts of the recording film are commonly known as “marks,” andthe crystallized part between any two marks is known as a “space.”Two-value binary information can thus be recorded using these marks andspaces. When a laser beam is emitted at a high power setting to form amark, the laser is referred to as operating at “peak power.” When thelaser is emitted at low power to form a space, the laser is said tooperate at a “bias power” level.

During data reproduction, a laser beam is emitted at a power level lowenough to not induce a phase change, and its reflection is thendetected. Reflectivity from an amorphous mark is normally low, and ishigh from a crystalline space. A read signal can therefore be generatedby detecting the difference in light reflected from the marks andspaces.

Data can also be recorded to a phase change disc using a mark positionrecording method (also known as PPM) or a mark edge recording method(also known as PWM). Mark edge recording normally achieves a higherrecording density.

Mark edge recording typically records longer marks than recorded by themark position recording method. When a laser emits at peak power to aphase change disc, heat accumulation in the recording film results inthe mark width increasing radially to the disc towards the end part ofthe mark. In a direct overwrite recording method this can result in partof a mark not being overwritten or completely erased, resulting in asignificant loss of signal quality due to signal crosstalk betweentracks during reproduction.

Recording density can also be increased by shortening the lengths of therecorded marks and spaces, Thermal interference can occur when thespaces, in particular, are shortened beyond a certain point. Thisthermal interference can result in heat at the trailing edge of arecorded mark travelling through the following space, thus affectingheat distribution at the beginning of the next mark. Heat at thebeginning of one recorded mark can also travel back through thepreceding space and adversely affect the cooling process of thepreceding mark. When such thermal interference occurs with conventionalrecording methods, the positions of the leading and trailing edges canshift, thus increasing the error rate during data reproduction.

Addressing this problem, Japanese Unexamined Patent ApplicationPublication (kokai) H07-129959 (U.S. Pat. Nos. 5,490,126 and 5,636,194)teaches a recording method whereby a signal for forming a mark in markedge recording is analyzed into three parts, a constant width beginningpart, a middle part having pulses with a constant period, and a constantwidth end part, and this signal is then used to drive recording byrapidly switching the output of a two-value laser beam during markformation.

With this method, the width of the middle part of a long mark issubstantially constant and does not spread because laser output isdriven with a constant period pulse current producing the minimum powerrequired for mark formation. Jitter at the leading and trailing edges ofthe mark also does not increase during direct overwrite recordingbecause a constant width laser beam is emitted to the leading andtrailing end parts of the mark.

It is also possible to detect whether a mark or spaces before and aftera mark is long or short, and change the position at which the leadingand trailing parts of a mark are recorded according to the length of themark and the leading and trailing spaces. This makes it possible tocompensate during recording for peak shifts caused by thermalinterference.

Japanese Patent Application 5-279513 does not, however, teach a methodfor determining the optimum positions of the leading and trailing partsof a mark.

If the method of optimizing the leading and trailing edge positions isnot defined, the reliability of the optimized recording will be low.Furthermore, even if optimized recording is achieved, it will be at theexpense of excessive time spent searching for the optimum position andexcessive circuit cost.

A method for changing the leading and trailing edge positions of a markbased on the data being recorded has also been invented as a means ofachieving high density data recording. A problem with this method,however, is that the edge of a recorded mark can move due to thermalinterference as described above. Such edge movement is also highlydependent upon the disc format and the makeup of the recording film, andif either of these change even slightly, optimized recording cannot beachieved.

With consideration for the above described problems, an object of thepresent invention is to provide a method and apparatus for easilydetermining the optimum positions the leading and trailing edges of eachmark, thereby achieving optimized recording, even when the disc format,recording film composition, and recording apparatus characteristicsvary.

SUMMARY OF THE INVENTION

To achieve these objects, according to the first aspect of theinvention, a data recording medium having a plurality of concentric orspiral tracks for recording information represented as marks and spacesbetween the marks, the marks being formed by emitting to a trackrecording surface an optical beam modulated by a plurality of drivepulses where the drive pulse count is adjusted according to a length ofa mark part in the original signal to be recorded to the track, saiddata recording medium comprises:

-   -   a data recording area for recording data, and    -   a specific information recording area for recording when the        data recording medium is loaded into a particular recording        device        -   device-specific information specific to the particular            recording device, and        -   at least one of a specific first pulse position Tu and a            specific last pulse position Td of a drive pulse sequence            required by the particular recording device to record said            marks to the data recording medium.

According to the second aspect of the invention, in the data recordingmedium as set forth in the first aspect, the device-specific informationincludes at least one of the following: a name of the particularrecording device manufacturer, a product number, a location where theparticular recording device was produced, and a production date.

According to the third aspect of the invention, in the data recordingmedium as set forth in the first aspect, the specific informationrecording area further records temporary power information indicative ofa power level of an optical beam used for determining at least one of aspecific first pulse position Tu and a specific last pulse position Td,

-   -   said temporary power information including at least one of the        following: a peak power setting, bias power setting, margin        constant, and asymmetry.

According to the fourth aspect of the invention, in the data recordingmedium as set forth in the second aspect, the specific informationrecording area further records a pattern signal for determining saidtemporary power information.

According to the fifth aspect of the invention, in the data recordingmedium as set forth in the first aspect, the specific informationrecording area further records operational power information indicativeof a power level of an optical beam used for actual data recording inthe data recording area,

-   -   said operational power information including at least one of the        following: a peak power setting, bias power setting, and margin        constant.

According to the sixth aspect of the invention, in the data recordingmedium as set forth in the fifth aspect, the specific informationrecording area further records a pattern signal for determining saidoperational power information.

According to the seventh aspect of the invention, in the data recordingmedium as set forth in the first aspect, said specific informationrecording area further records an asymmetry information used fordetermining at least one of a specific first pulse position Tu and aspecific last pulse position Td.

According to the eighth aspect of the invention, in the data recordingmedium as set forth in the first aspect, further comprises:

-   -   a control information recording area for prerecording at least        one of a typical first drive pulse position Tu and a typical        last drive pulse position Td of a drive pulse sequence required        for recording said marks to the data recording medium.

According to the ninth aspect of the invention, in the data recordingmedium as set forth in the first aspect, said specific informationrecording area is provided for recording at least one of a specificfirst pulse position Tu and a specific last pulse position Td, and adevice-specific information as a data set, said data set being recordedfor a plurality of different recording devices.

According to the tenth aspect of the invention, in the recording andreproducing device for recording information to and reproducinginformation from a data recording medium,

-   -   said data recording medium having a plurality of concentric or        spiral tracks for recording information represented as marks and        spaces between the marks, the marks being formed by emitting to        a track recording surface an optical beam modulated by a        plurality of drive pulses where the drive pulse count is        adjusted according to a length of a mark part in the original        signal to be recorded to the track,    -   a data recording area for recording data, and    -   a specific information recording area for recording when the        data recording medium is loaded into a particular recording        device        -   device-specific information specific to the particular            recording device, and        -   at least one of a specific first pulse position Tu and a            specific last pulse position Td of a drive pulse sequence            required by the particular recording device to record said            marks to the data recording medium,    -   the recording and reproducing device comprises:    -   a reading means for reading device-specific information specific        to the data recording medium from a particular area of the data        recording medium; and    -   memory for storing said read medium-specific information.

According to the eleventh aspect of the invention, in the recording andreproducing device as set forth in the tenth aspect, the medium-specificinformation includes at least one of the following: a name of the datarecording medium manufacturer, a product number, a location where thedata recording medium was produced, and a production date.

According to the twelfth aspect of the invention, in the recording andreproducing device as set forth in the tenth aspect, the memory furtherstores temporary power information indicative of a power level of anoptical beam used for determining a specific first pulse position Tuand/or specific last pulse position Td,

-   -   said temporary power information including at least one of the        following: a peak power setting, bias power setting, margin        constant, and asymmetry.

According to the thirteenth aspect of the invention, in the recordingand reproducing device as set forth in the twelfth aspect, the memoryfurther stores a pattern signal for determining said temporary powerinformation.

According to the 14th aspect of the invention, in the recording andreproducing device as set forth in the tenth aspect, the memory furtherstores operational power information indicative of a power level of anoptical beam used for actual data recording in the data recording area,

-   -   said operational power information including at least one of the        following a peak power setting, bias power setting, and margin        constant.

According to the 15th aspect of the invention, in the recording andreproducing device as set forth in the 14th aspect, the memory furtherstores a pattern signal for determining said operational powerinformation.

According to the 16th aspect of the invention, in the recording andreproducing device as set forth in the tenth aspect, said memory furtherrecords an asymmetry information used for determining at least one of aspecific first pulse position Tu and a specific last pulse position Td.

According to the 17th aspect of the invention, in the recording andreproducing device as set forth in the tenth aspect, the memory furtherstores said specific first pulse position Tu and/or said specific lastpulse position Td.

According to the 18th aspect of the invention, in the recording andreproducing device as set forth in the tenth aspect, the memory furtherstores medium-specific information for a plurality of different datarecording media used in the recording and reproducing device.

According to the 19th aspect of the invention, in a recording method forrecording to a data recording medium, said data recording medium havinga plurality of concentric or spiral tracks for recording informationrepresented as marks and spaces between the marks, the marks beingformed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track,

-   -   a data recording area for recording data, and    -   a specific information recording area for recording when the        data recording medium is loaded into a particular recording        device        -   device-specific information specific to the particular            recording device, and        -   at least one of a specific first pulse position Tu and a            specific last pulse position Td of a drive pulse sequence            required by the particular recording device to record said            marks to the data recording medium,    -   the recording method comprises steps for:    -   determining said specific first pulse position Tu and/or said        specific last pulse position Td; and    -   then recording data to the data recording area.

According to the 20th aspect of the invention, in the recording methodas set forth in the 19th aspect, the specific first pulse position Tu isobtained from a length of a mark part and immediately preceding spacepart in a pattern signal, and

-   -   the specific last pulse position Td is obtained from a length of        a mark part and immediately following space part in a pattern        signal.

According to the 21st aspect of the invention, in the recording methodas set forth in the 19th aspect, the specific first pulse position Tu isexpressed as a time difference TF between a first reference point R1,which is a leading edge of a mark part in the pattern signal to berecorded, and a first edge of the first pulse in a plurality of drivepulses, and specific last pulse position Td is expressed as a timedifference TL between a second reference point R2, which has a specificknown position relative to a trailing edge of a mark part in the patternsignal to be recorded, and a trailing edge of the last pulse in aplurality of drive pulses.

According to the 22nd aspect of the invention, in the recording methodas set forth in the 20th aspect, the pattern signal contains anadjustment signal for obtaining a DSV of 0.

According to the 23rd aspect of the invention, in the recording methodas set forth in the 19th aspect, the specific first pulse position Tuand/or specific last pulse position Td is determined by reproducing aspecific information recording area of the data recording medium toobtain necessary information.

According to the 24th aspect of the invention, in the recording methodas set forth in the 19th aspect, the specific first pulse position Tuand/or specific last pulse position Td is determined by readinginformation from memory in a particular recording and reproducing devicein which the data recording medium is used to obtain necessaryinformation.

According to the 25th aspect of the invention, in the recording methodas set forth in the 19th aspect, the information determined for thespecific first pulse position Tu and/or specific last pulse position Tdis recorded to the specific information recording area of the datarecording medium in conjunction with device-specific informationspecific to the particular recording and reproducing device.

According to the 26th aspect of the invention, in the recording methodas set forth in the 19th aspect, the information determined for thespecific first pulse position Tu and/or specific last pulse position Tdis recorded in memory in a particular recording and reproducing devicein conjunction with device-specific information specific to theparticular recording and reproducing device.

According to the 27th aspect of the invention, in the recording methodas set forth in the 19th aspect, temporary power information indicativeof a power level of an optical beam used for determining a specificfirst pulse position Tu and/or specific last pulse position Td isfurther recorded to the specific information recording area of the datarecording medium,

-   -   said temporary power information including at least one of the        following: a peak power setting, bias power setting, margin        constant, and asymmetry.

According to the 28th aspect of the invention, in the recording methodas set forth in the 27th aspect, a pattern signal for determining saidtemporary power information is further recorded to said specificinformation recording area.

According to the 29th aspect of the invention, in the recording methodas set forth in the 19th aspect, operational power informationindicative of a power level of an optical beam used for actual datarecording in the data recording area is further recorded to the specificinformation recording area of the data recording medium,

-   -   said operational power information including at least one of the        following: a peak power setting, bias power setting, and margin        constant.

According to the 30th aspect of the invention, in the recording methodas set forth in the 29th aspect, a pattern signal for determining saidoperational power information is further recorded to said specificinformation recording area.

According to the 31st aspect of the invention, in the recording methodas set forth in the 19th aspect, said specific information recordingarea further records an asymmetry information used for determining atleast one of a specific first pulse position Tu and a specific lastpulse position Td.

According to the 32nd aspect of the invention, in the recording methodfor recording to a data recording medium, said data recording mediumhaving a plurality of concentric or spiral tracks for recordinginformation represented as marks and spaces between the marks, the marksbeing formed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track,

-   -   a data recording area for recording data, and    -   a specific information recording area for recording when the        data recording medium is loaded into a particular recording        device        -   device-specific information specific to the particular            recording device, and        -   at least one of a specific first pulse position Tu and a            specific last pulse position Td of a drive pulse sequence            required by the particular recording device to record said            marks to the data recording medium,    -   the recording method comprises steps for:    -   determining emission power of an optical beam for recording said        marks; and    -   then determining a specific first pulse position Tu and/or        specific last pulse position Td.

According to the 33rd aspect of the invention, in the recording methodas set forth in the 32nd aspect, the optical beam emission power isdetermined by recording a predetermined specified pattern signal to thedata recording medium.

According to the 34th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the specified pattern signal contains asingle signal.

According to the 35th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the specified pattern signal containsan adjustment signal for obtaining a DSV of 0.

According to the 36th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the specific pattern signal recorded tothe data recording medium is reproduced, the reproduced specific patternsignal is compared with a specific pattern signal for recording, and theemission power is set so that a difference between the compared signalsis a specific value or less.

According to the 37th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the predetermined specific patternsignal is prerecorded to the data recording medium.

According to the 38th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the predetermined specific patternsignal is prerecorded in the recording device.

According to the 39th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the emission power determined for aspecific data recording medium is recorded to said specific datarecording medium.

According to the 40th aspect of the invention, in the recording methodas set forth in the 33rd aspect, the emission power determined for aspecific data recording medium is stored in the recording device inconjunction with the medium-specific information for said specific datarecording medium.

According to the 41st aspect of the invention, in the recording methodas set forth in the 32nd aspect, temporary power information indicativeof a power level of an optical beam used for determining a specificfirst pulse position Tu and/or specific last pulse position Td isfurther recorded to the specific information recording area of the datarecording medium, said temporary power information including at leastone of the following: a peak power setting, bias power setting, marginconstant, and asymmetry.

According to the 42nd aspect of the invention, in the recording methodas set forth in the 41st aspect, wherein a pattern signal fordetermining said temporary power information is further recorded to saidspecific information recording area.

According to the 43rd aspect of the invention, in the recording methodas set forth in the 32nd aspect, operational power informationindicative of a power level of an optical beam used for actual datarecording in the data recording area is further recorded to the specificinformation recording area of the data recording medium, saidoperational power information including at least one of the following: apeak power setting, bias power setting, and margin constant.

According to the 44th aspect of the invention, in the recording methodas set forth in the 43rd aspect, a pattern signal for determining saidoperational power information is further recorded to said specificinformation recording area.

According to the 45th aspect of the invention, in a recording method forrecording to a data recording medium, said data recording medium havinga plurality of concentric or spiral tracks for recording informationrepresented as marks and spaces between the marks, the marks beingformed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track,

-   -   a data recording area for recording data, and    -   a specific information recording area for recording when the        data recording medium is loaded into a particular recording        device        -   device-specific information specific to the particular            recording device, and        -   at least one of a specific first pulse position Tu and a            specific last pulse position Td of a drive pulse sequence            required by the particular recording device to record said            marks to the data recording medium,    -   the recording method comprises steps for:    -   determining a specific first pulse position Tu and/or specific        last pulse position Td, and    -   then determining emission power of an optical beam for recording        said marks.

According to the 46th aspect of the invention, in the recording methodas set forth in the 45th aspect, the optical beam emission power isdetermined by recording a predetermined specified pattern signal to thedata recording medium.

According to the 47th aspect of the invention, in the recording methodas set forth in the 46th aspect, the predetermined specific patternsignal is prerecorded to the data recording medium.

According to the 48th aspect of the invention, in the recording methodas set forth in the 46th aspect, the predetermined specific patternsignal is prerecorded in the recording device.

According to the 49th aspect of the invention, in the recording methodas set forth in the 46th aspect, the emission power determined for aspecific data recording medium is recorded to said specific datarecording medium.

According to the 50th aspect of the invention, in the recording methodas set forth in the 46th aspect, the emission power determined for aspecific data recording medium is stored in the recording device inconjunction with the medium-specific information for said specific datarecording medium.

According to the 51 st aspect of the invention, in the recording methodas set forth in the 45th aspect, temporary power information indicativeof a power level of an optical beam used for determining a specificfirst pulse position Tu and/or specific last pulse position Td isfurther recorded to the specific information recording area of the datarecording medium,

-   -   said temporary power information including at least one of the        following: a peak power setting, bias power setting, margin        constant, and asymmetry.

According to the 52nd aspect of the invention, in the recording methodas set forth in the 51st aspect, a pattern signal for determining saidtemporary power information is further recorded to said specificinformation recording area.

According to the 53rd aspect of the invention, in the recording methodas set forth in the 45th aspect, operational power informationindicative of a power level of an optical beam used for actual datarecording in the data recording area is further recorded to the specificinformation recording area of the data recording medium,

-   -   said operational power information including at least one of the        following: a peak power setting, bias power setting, and margin        constant.

According to the 54th aspect of the invention, in the recording methodas set forth in the 53rd aspect, a pattern signal for determining saidoperational power information is further recorded to said specificinformation recording area.

According to the 55th aspect of the invention, in the recording methodas set forth in the 45th aspect, said specific information recordingarea further records an asymmetry information used for determining atleast one of a specific first pulse position Tu and a specific lastpulse position Td.

According to the 56th aspect of the invention, in a recording method forrecording to a data recording medium, said data recording medium havinga plurality of concentric or spiral tracks for recording informationrepresented as marks and spaces between the marks, the marks beingformed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track,

-   -   a data recording area for recording data, and    -   a specific information recording area for recording when the        data recording medium is loaded into a particular recording        device        -   device-specific information specific to the particular            recording device, and in conjunction therewith        -   at least one of a specific first pulse position Tu and a            specific last pulse position Td of a drive pulse sequence            required by the particular recording device to record said            marks to the data recording medium,    -   the recording method comprises steps for:    -   compensating for group delay so that a same group delay level is        obtained in a read signal even when the frequency of the        recorded signal differs; and    -   then determining a specific first pulse position Tu and/or        specific last pulse position Td.

According to the 57th aspect of the invention, in the recording methodas set forth in the 56th aspect, wherein group delay compensation isaccomplished by recording a test signal having a space signal componentof a specific length to the data recording medium.

According to the 58th aspect of the invention, in the recording methodas set forth in the 57th aspect, wherein the test signal is an embossedsignal prerecorded to the data recording medium.

According to the 59th aspect of the invention, in the recording methodas set forth in the 57th aspect, the test signal is prerecorded to aspecific area of the data recording medium.

According to the 60th aspect of the invention, in the recording methodas set forth in the 57th aspect, the test signal is prerecorded to therecording device.

According to the 61st aspect of the invention, in the recording methodas set forth in the 57th aspect, group delay compensation is performedto minimize jitter in the reproduced test signal.

According to the 62nd aspect of the invention, in the recording methodas set forth in the 56th aspect, temporary power information indicativeof a power level of an optical beam used for determining a specificfirst pulse position Tu and/or specific last pulse position Td isfurther recorded to the specific information recording area of the datarecording medium,

-   -   said temporary power information including at least one of the        following: a peak power setting, bias power setting, margin        constant, and asymmetry.

According to the 63rd aspect of the invention, in the recording methodas set forth in the 62nd aspect, a pattern signal for determining saidtemporary power information is further recorded to said specificinformation recording area.

According to the 64th aspect of the invention, in the recording methodas set forth in the 56th aspect, operational power informationindicative of a power level of an optical beam used for actual datarecording in the data recording area is further recorded to the specificinformation recording area of the data recording medium,

-   -   said operational power information including at least one of the        following: a peak power setting, bias power setting, and margin        constant.

According to the 65th aspect of the invention, in the recording methodas set forth in the 64th aspect, a pattern signal for determining saidoperational power information is further recorded to said specificinformation recording area.

According to the 66 th aspect of the invention, in the recording methodas set forth in the 56th aspect, said specific information recordingarea further records an asymmetry information used for determining atleast one of a specific first pulse position Tu and a specific lastpulse position Td.

According to the 67th aspect of the invention, in a data recordingmedium having a plurality of concentric or spiral tracks for recordinginformation represented as marks and spaces between the marks, the marksbeing formed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track, said data recording medium comprises:

-   -   a data recording area for recording data, and    -   a control data zone for prerecording control data as a sequence        of embossed marks and spaces,        -   said control data including at least one of a first pulse            position Tu and a last pulse position Td of a drive pulse            sequence required by a recording device to record said marks            to the data recording medium, and        -   temporary power information indicative of a power level of            an optical beam used for determining a said first pulse            position Tu and/or last pulse position Td,            -   said temporary power information including at least one                of the following: a peak power setting, bias power                setting, margin constant, and asymmetry.

According to the 68th aspect of the invention, in a data recordingmedium having a plurality of concentric or spiral tracks for recordinginformation represented as marks and spaces between the marks, the marksbeing formed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track, said data recording medium comprises:

-   -   a data recording area for recording data, and    -   a control data zone for prerecording control data as a sequence        of embossed marks and spaces,        -   said control data including at least one of a first pulse            position Tu and a last pulse position Td of a drive pulse            sequence required by a recording device to record said marks            to the data recording medium, and        -   operational power information indicative of a power level of            an optical beam used for actual data recording in the data            recording area,            -   said operational power information including at least                one of the following: a peak power setting, bias power                setting, and margin constant.

According to the 69th aspect of the invention, in a data recordingmedium having a plurality of concentric or spiral tracks for recordinginformation represented as marks and spaces between the marks, the marksbeing formed by emitting to a track recording surface an optical beammodulated by a plurality of drive pulses where the drive pulse count isadjusted according to a length of a mark part in the original signal tobe recorded to the track, said data recording medium comprises:

-   -   a data recording area for recording data, and    -   a control data zone for prerecording control data as a sequence        of embossed marks and spaces,        -   said control data including at least one of a first pulse            position Tu and a last pulse position Td of a drive pulse            sequence required by a recording device to record said marks            to the data recording medium, and        -   an asymmetry information used for determining said pulse            positions.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a recording device for informationaccording to a preferred embodiment of the present invention;

FIG. 2 is a plan view of an optical disc according to a preferredembodiment of the present invention;

FIGS. 3 and 6 to 9 are used to described signal processing according toa method of the present invention;

FIG. 4 shows recording pulse sequences according to a method of thepresent invention;

FIGS. 5A and 5B show a preferred method of grouping signals according toa method of the present invention;

FIGS. 10 and 11 are used to describe interpolation of the initial valuesused for edge position adjustment according to a preferred embodiment ofthe present invention;

FIGS. 12 to 18 are plan views of exemplary optical discs according topreferred embodiments of the present invention;

FIG. 19 is used to describe determining the temporary power emissionlevel before edge position adjustment according to a preferredembodiment of the present invention;

FIGS. 20A, 20B and 20C show an exemplary recording pattern in apreferred embodiment of the present invention;

FIG. 21 is used to describe a method for determining the peak powerlevel before edge position adjustment according to a preferredembodiment of the present invention;

FIGS. 22 and 23 are used to describe a method for determining the biaspower level before edge position adjustment according to a preferredembodiment of the present invention;

FIG. 24 is used to describe a method for determining the peak powerlevel after edge position adjustment according to a preferred embodimentof the present invention;

FIG. 25 is used to describe a method for determining the bias powerlevel after edge position adjustment according to a preferred embodimentof the present invention;

FIG. 26 shows the frequency characteristic of group delay in thereproduction system of a disc recorder according to a preferredembodiment of the present invention;

FIG. 27 shows a data reproduction signal in a preferred embodiment ofthe present invention;

FIGS. 28A and 28B show a method of detecting group delay in a preferredembodiment of the present invention;

FIGS. 29A and 29B are block diagrams of a group delay compensationcircuit in a preferred embodiment of the present invention;

FIG. 30 shows the relationship between jitter and group delaycompensation in a preferred embodiment of the present invention;

FIGS. 31A, 31B and 31C show the user data format in a typical opticaldisc;

FIGS. 32, 33 and 36 are used to describe signal processing by a methodaccording to a preferred embodiment of the present invention;

FIGS. 34 and 35 show the data format of an optical disc according to apreferred embodiment of the present invention;

FIG. 37 shows the format of data storage in memory 130 according to apreferred embodiment of the present invention; and

FIG. 38 summarizes the features of various embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention are described belowwith reference to the accompanying figures.

FIG. 1 is a block diagram of an optical data recording apparatus,referred to below as an optical disc recorder, according to thepreferred embodiment of the present invention.

Shown in FIG. 1 are: an optical disc 101, spindle motor 102,semiconductor laser 103, collimeter lens 104, beam splitter 105,objective lens 106, collective lens 107, photodetector 108, laser drivecircuit 109, pulse moving circuit 110, pulse generator 111, preamplifier112, low pass filter 113, reproduction equalizer 114, digitizing circuit115, PLL 116, demodulation circuit 117, error correction circuit 118,power level setting circuit 119, pulse position offset measuring circuit120, switch 121, switch contacts 122, 123, and 124, pattern signalgenerator 125 for pulse position adjusting, modulation circuit 126,recording data generator 127, read data signal 128, memory 129, memory130, data comparator 131, and memory 132.

The recording data generator 127 further comprises a unique patterngenerator 127 a, a random pattern generator 127 b, and a real signalgenerator 127 c.

Also shown in FIG. 1 are delay circuits 138 and 139, each having thesame delay time, and an asymmetry detector 140.

Memory 129 stores two tables which are corrected by the method of thepresent invention as shown in FIG. 5 with the corrected tables thenwritten back to memory.

Memory 132 stores information used for determining the power level usedto drive the laser, and stores the final power setting selected. Notethat in this exemplary embodiment of the present invention laser drivepower is set to either the above-noted peak power level or bias powerlevel.

Memory 130 stores (1) disc-specific information that is prewritten tothe optical disc (such as the name of the optical disc manufacturer,product number, manufacturing location, date of production, discstructure, and recording film composition), (2) the adjustment method asfurther described below, (3) the above-noted two tables corrected andstored in memory 129, and (4) the selected laser power level stored tomemory 132. It is to be noted that memory 130 stores the above contents(1) to (4) for a plurality of different optical discs.

By thus storing this information in memory for a plurality of differentoptical discs, operations for obtaining information required to preparethe recording device for optimized recording, particularly operationsfor obtaining the above-noted items (3) and (4), can be skipped when anoptical disc is loaded for data recording if the above-noted content (1)to (4) is already stored in memory for the loaded disc. It is thereforepossible to immediately begin recording.

A conceptual map for the data layout in memory 130 is shown in FIG. 37.The above-noted content (1) is contained in disc-specific information n;content (2) and (3) is contained in the pulse position information; andcontent (4) is contained in the temporary power and operational powerlevel information. When a disc is loaded in a recording device, referredto hereafter as a disc recorder, the disc-specific information is readimmediately from the disc. The disc-specific information read from discis then compared with the disc-specific information stored to memory 130to determine whether the same information is already in memory.

If the same information is not already in memory, such as when a newdisc is loaded into the disc recorder for the first time, thedisc-specific information, temporary power and operational power levelinformation, and pulse position information are stored as one set ofdata to memory 130. It is to be noted that anywhere from several secondsto ten several seconds may be required to obtain the temporary power andoperational power level information and pulse position informationthrough a test recording operation as described herein.

If a data set matching the read disc-specific information is already inmemory, that is, if the same disc has been previously loaded into thedisc recorder, the temporary power and operational power levelinformation and pulse position information for the data set matching thedisc-specific information read from disc is read from memory 130. Thetemporary power and operational power level information is then writtento memory 132 and the pulse position information is written to memory129. It is to be noted that because this information can be simply readfrom memory, the several seconds to ten several seconds required todetermine the information through a test recording operation is saved.

It will thus be obvious that if n different discs are loaded into thedisc recorder, n sets of disc-specific information, temporary power andoperational power level information, and pulse position information willbe written to memory 130. In a preferred embodiment of the presentinvention these n data sets are stored to two or more locations. Bystoring the data sets to a plurality of locations, the data can bereproduced from a second location, for example, if reading data from onelocation in memory 130 is disabled due to a scratch or contamination,for example.

FIG. 2 is a plan view of the optical disc 101, which has a data storagearea 201 and a writing test zone 202.

It is to be noted that the optical head of the data recorder shown inFIG. 1 comprises the semiconductor laser 103, collimator lens 104, beamsplitter 105, objective lens 106, collective lens 107, and photodetector108. When an optical disc 101 is loaded to the optical data recorder,the optical head moves to the writing test zone 202, which is used fordetermining the optimum positions for the start position and endposition of each mark.

This area for determining the optimum mark start and end positions is anarea at the inside circumference area and/or the outside circumferencearea of the disc, and is outside of the user data recording area. Anexemplary area is the drive test zone of the disc. Switch 121 switchescontact 122 to contact 123 when writing to the writing test zone 202.During normal user data writing operations, the switch 121 changes sothat contact 122 is conductive to contact 124 so that the output signalfrom the recording data generator 127 is applied to the pulse generator111 after it has been modulated by the modulation circuit 126.

The power level setting circuit 119 sets the laser drive circuit 1-09 toeither peak power or bias power. At this time the output signal frompattern signal generator 125 is passed by switch 121 to the pulsegenerator 111. Signal flow from the pulse generator 111 is describedfurther below with reference to FIG. 3.

Shown in FIG. 3 are a first pattern signal 301, which is the outputsignal from the pattern signal generator 125; output signal 302 from thepulse generator 111; output signal 303 from the pulse moving circuit110; and mark pattern 304 formed in the recording track of the opticaldisc 101 as a result of modulating laser power output between peak powerand bias power levels according to output signal 303. It is to be notedthat while signals 301, 302, and 303 are not generated on the same timebase, for convenience they are shown with corresponding parts in eachsignal aligned vertically.

In first pattern signal 301, mark parts 309, 311, 313, 315, 317, and 319are the parts of the signal whereby a mark is to be formed on the disc,and space parts 310, 312, 314, 316, 318, and 320 are the parts of thesignal that appear as a space on disc. It is further assumed below thatmark part 309 follows space part 320 such that first pattern signal 301comprises a repeating pattern of parts 309 to 320.

For example, when data generated by (2,10) run-length limited modulationis recorded using a mark edge recording method, the marks and spaceshave a shortest length of 3T and a longest length of 11T where T is thereference period. Mark part 309 is a 6T signal (a 6T mark part below),space part 310 is a 6T space, 311 is a 3T mark, 312 is a 6T space, 313is a 6T mark, 314 is a 6T space, 315 is a 6T mark, 316 is a 4T space,317 is a 6T mark, 318 is a 6T space, 319 is a 7T mark, and 320 is a 6Tspace.

Note that if DSV is the difference of the sum of mark and space lengthsin a specific period, a reproduction signal with a small dc component orlow frequency component can be obtained when the marks and spaces arereproduced by inserting signals 319 and 320 whereby a DSV ofsubstantially zero can be obtained; note that signals 319 and 320 areinserted only when DSV is otherwise not zero. Reproducing a signal withmany dc components or low frequency components can result in thedigitizing circuit 115 erroneously generating a signal with the wrongsequence of 0s and 1s.

To prevent this, a 7T mark part 319 is inserted to the first patternsignal 301 as a compensation signal assuring that the DSV issubstantially 0. More specifically, first pattern signal 301 isgenerated so that the sum (34T) of the periods of mark parts 309, 311,313, 315, 317, and 319 is equal to the sum (34T) of the space parts 310,312, 314, 316, 318, and 320. DSV is calculated by adding the periods ofthe mark parts as positive values and the periods of the space parts asnegative values. As a result, the DSV of first pattern signal 301 is 0.

This first pattern signal 301 is converted to a pulse sequence by thepulse generator 111, resulting in pulse generator output signal 302.Pulse output from the pulse generator 111 corresponding to marks oflengths from 3T to 11T is shown in FIG. 4.

Referring by way of example to a 6T signal in FIG. 4, the pulse at thestart of the signal is referred to as the first pulse 401, and the pulseat the end of the signal is the last pulse 404. The pulses between thefirst pulse 401 and last pulse 404 are referred to as multiple pulses402 and 403, and have a constant period.

In a 6T mark there are two multiple pulses 402 and 403, in a 7T markthere are three, and in a 5T mark there is one. It will thus be obviousthat the number of multiple pulses 402 between the first and last pulsesincreases by one with each 11T increase in signal length, and decreasesone with each 1T decrease in signal length. A 4T mark, thereforecomprises only the first and last pulses, and has no multiple pulses 402or 404 therebetween. In addition, a 3T mark comprises just one pulse.

It is to be noted that in this exemplary embodiment of the presentinvention the time-base length of the first pulse is 1.5T, the lastpulse is 0.5T, and the length of the multiple pulses is also 0.5T. Theinvention shall not be so limited, however, and the length, count, orperiod of these pulses can be varied as necessary according to thestructure of the optical disc 101.

The pulse generator output signal 302 is input to the pulse movingcircuit 110, which generates and outputs a signal 303 in which thepositions of the first pulse and last pulse are moved. FIG. 5 shows thecombinations of marks and spaces used for shifting the first pulse andlast pulse positions.

FIG. 5(a) shows the pulse movement tables after correction by the methodof this present invention, and FIG. 5(b) shows the tables beforecorrection. Symbols 3S3M, 4S3M, and so forth in the tables in FIG. 5(a)are a type of address, and are indicative of the signal type as well asthe value written to that address. When read as an address, the value3S3M, for example, represents a signal in which a 3T mark follows a 3Tspace. As will be described more fully below, the value of the firstpulse movement TF stored at the place indicated by 3S3M is the movementrequired when a 3T mark follows a 3T space.

These first pulse movement TF values are obtained by, for example, atrial and error process using a particular optical test disc, and theresulting values are compiled in the tables in FIG. 5(a). The content ofthe completed table is stored for all optical discs having the samestructure as the optical test disc. Predetermined initial values arestored in the table on the left in FIG. 5(b) for the first pulse. Thetable on the right in FIG. 5(b) stores the initial values beforecorrecting last pulse movement.

The position of the first pulse, that is, first drive pulse position Tu,changes according to the length of the mark and the immediatelypreceding space. In this preferred embodiment, the marks and spaces areseparated into three groups, that is, 3T, 4T, and 5T or longer. A totalof nine different pulse positions are therefore defined.

The position of the last pulse, that is, last drive pulse position Td,likewise changes according to the length of the mark and the immediatelyfollowing space. In this preferred embodiment, the marks and spaces areseparated into three groups, that is, 3T, 4T, and 5T or longer. A totalof nine different pulse positions are therefore defined.

It is to be noted that a preferred method for determining first and lastpulse movement is taught in the related Japanese Patent Application11-185298, U.S. patent application Ser. No. 09/352,211, and EuropeanPatent Application No. 99113060.0, which were filed by the presentinventor and are incorporated herein by reference.

FIG. 33 is an enlarged view of the 6T mark 317 in the first patternsignal 301 shown in FIG. 3, and the corresponding part in the pulsegenerator output signal 302. As shown in the figure, a 4T space 316 isimmediately before the 6T mark 317. A 4T space followed by a 6T markbelongs to the 4S5M group in the left table in FIG. 5(a). Correcting theinitial first pulse movement TF stored for this group is describedbelow.

The pattern signal generator 125 in the optical data recorder shown inFIG. 1 generates a first pattern signal 301. This first pattern signal301 is sent to the pulse generator 111, delay circuit 139, pulseposition offset measuring circuit 120, and memory 129. As noted above,the two tables shown in FIG. 5(b) are prestored to memory 129. The pulseposition offset measuring circuit 120 also stores the first patternsignal 301, which is used for comparison with the reproduction signalduring data reproduction. The pulse generator 111 generates the outputsignal 302 required for recording the pattern signal. Referring to thesignals shown on the top two rows in FIG. 4, for example, the pulsegenerator 111 generates a first pulse 401 corresponding to the risingedge of the mark in the first pattern signal 301, then outputs multiplepulses 402 and 403, and last pulse 404.

The pulse generator output signal 302 is delayed a predetermined periodby the delay circuit 138, and then passed to the pulse moving circuit110. This predetermined period is 13T in this exemplary embodiment. Thefirst pattern signal 301 is analyzed in memory 129 to determine to whichof the 18 signal groups, that is, 3S3M, 3S4M, 3S5M, 4S3M, 4S4M, 4S5M,5S3M, 5S4M, 5S5M, 3M3S, 4M3S, 5M3S, 3M4S, 4M4S, 5M4S, 3M5S, 4M5S, and5M5S, the signal in the preceding 10T or longer period belongs. Forexample, if a 4T space 316 is followed by a 6T mark 317 in the firstpattern signal 301 from the pattern signal generator 125, memory 129detects that the signal belongs to the 4S5M group. Memory 129 thereforereads and outputs to the pulse moving circuit 110 the amount of movementstored in the table at 4S5M0. The initial 4S5M0 movement value is readfrom the table the first time a movement value is read. The pulse movingcircuit 110 then moves the first pulse of the pulse generator outputsignal 302 supplied thereto after a predetermined delay based on theinitial movement value read from 4S5M0.

Movement of the first pulse is described in further detail below withreference to FIG. 1 and FIG. 33. When the pulse moving circuit 110 isnotified by memory 129 that a pattern belonging to a specific group willsoon arrive from the delay circuit 139, it also receives the first pulsemovement TF for that pattern from the memory 129. For example, when thememory 129 informs the pulse moving circuit 110 that a pattern belongingto the 4S5M group, that is, a 4T space 316 following by a 6T mark 317,will arrive from the delay circuit 139, it also sends the first pulsemovement TF read for the 4S5M0 group. The pulse moving circuit 110 thenbegins counting first pulse movement TF at the rising pulse edge of the6T mark 317 received from the delay circuit 139, that is, at time R1 inFIG. 33. Output of the first pulse from the delay circuit 138 is delayedfor the period counted by the pulse moving circuit 110, that is, forpulse movement TF.

When first pulse movement TF is referenced to the rising edge R1 of thefirst pattern signal 301, for example, first pulse movement TF isexpressed as the time difference from reference time R1 as shown in FIG.33. In this exemplary embodiment, pulse movement TF is approximately 3ns. It is to be noted that the first pulse is moved without changing thepulse width.

The pattern signal shown in FIG. 3 contains signal components belongingto four of the 18 groups in the table shown in FIG. 5(a): type 3M5S inperiod 321, type 5S3M in period 322, type 4S5M in period 323, and type5M4S in period 324. Each of the pulse signal components corresponding tothese four types in first pattern signal 301 is therefore moved.

The laser is then driven according to these moved pulses to record theactual marks. The resulting marks 304 are shown in FIG. 3. In thispreferred embodiment of the present invention, the first pattern signal301 comprising elements 309 to 320 as shown in FIG. 3 is outputrepeatedly and recorded around one track. When recording one completetrack is thus completed, the track is reproduced. Reproduction includesconverting an optical signal from the photodetector 108 to an electricalsignal, and then processing this electrical signal with preamplifier112, low pass filter 113, reproduction equalizer 114, and digitizingcircuit 115 to obtain reproduction signal 305. The reproduction signal305 is input to pulse position offset measuring circuit 120. Thereproduction signal 305 from a single track is thus input repeatedly tothe pulse position offset measuring circuit 120. The pulse positionoffset measuring circuit 120 thus reads each of the periods 321, 322,323, and 324 associated with different signal types multiple times, andcalculates the average for each period.

The pulse position offset measuring circuit 120 compares the periods321, 322, 323, 324 corresponding to the types obtained in the recordedfirst pattern signal 301 during recording, and the averages for the sameperiods obtained from the reproduction signal 305 to detect whether anyshifting in pulse position has occurred. Using by way of example thesignals recorded and reproduced as described above, the combined time ofthe 4T space 316 and 6T mark 317 in the first pattern signal 301 iscompared with the average obtained for the corresponding period 324 inthe reproduction signal 305, and the difference therebetween isobtained. If there is a difference, the pulse position offset measuringcircuit 120 determines that the pulse position shifted, and thecalculated difference is therefore sent to memory 129. Because thisdifference is the result of the initial movement value 4S5M0, thisinitial movement value 4S5M0 is increased or decreased in memory 129according to the difference, thereby correcting the stored movementvalue. This corrected value is then overwritten to type 4S5M.

It is to be noted that the stored movement value is corrected andoverwritten to 4S5M using a single feedback loop (through 110, 109, 108,112, 115, 120, 126, 129) in the above exemplary embodiment. It will beobvious, however, that a plurality of feedback loops can bealternatively used to correct the value of the first pulse movement TFas shown in FIG. 33.

Movement of the last pulse position is similarly corrected. That is,last pulse position movement changes according to the mark length andthe length of the following space. In this exemplary embodiment marksand spaces are separated into three groups based on length, 3T, 4T, and5T or longer, and pulse position movement is defined for each of thenine possible mark/space combinations. The last pulse movement TL isthen calculated using the same method used to calculate first pulsemovement TF.

As shown in FIG. 33, last pulse movement TL is corrected in the samemanner as the first pulse movement TF described above. This last pulsemovement TL is the time interval from time reference R2 offset 2Tforward of the trailing edge of the mark to the trailing edge of thelast pulse, and is corrected by means of the loop described above withreference to the first pulse. The last pulse movement TL isapproximately 11 ns in this exemplary embodiment. It is to be also notedthat the width of the last pulse does not change even though the amountof last pulse movement TL changes, and in this exemplary embodiment thepulse width remains the same with the pulse simply shifted on the timeaxis.

The output signal 306 from the pulse moving circuit 110 obtained usingthe corrected pulse movement tables shown in FIG. 5(a), the marks 307recorded as a result of this output signal 306, and the reproductionsignal 308 reproduced from these marks 307, are also shown in FIG. 3.While the reproduction signal 305 obtained using the original,uncorrected pulse movement table (FIG. 5(b)) is not identical to theoriginal pattern signal 301, there is substantially no differencebetween the reproduction signal 308 obtained using the corrected pulsemovement table (FIG. 5(a)) and the original pattern signal 301.

It is to be noted that four of the eighteen pulse movement values arecorrected as described above using the first pattern signal 301 shown inFIG. 3. The other values are similarly corrected using other patternsignals. More specifically, types 4M5S, 5S4M, 3S5M, and 5M3S arecorrected using a pattern signal 601 as shown in FIG. 6; types 4M4S,3M3S, 4S4M, 3S3M are corrected using a pattern signal 701 as shown inFIG. 7; types 4M3S, 4S3M are corrected using a pattern signal 801 asshown in FIG. 8; and types 3M4S, 3S4M are corrected using a patternsignal 901 as shown in FIG. 9.

It is to be noted that types 5M5S and 5S5M can be corrected using apattern signal 3201 as shown in FIG. 32, or a default value therefor canbe simply defined. It is to be noted that types 5M5S and 5S5M arepreferably corrected before the other types. This is because these marksand spaces have the longest period and are therefore least affected bythermal interference. The delay period is therefore small, and can beused as a reference value for determining the other delay periods.

It is to be noted that a predetermined initial value is set as shown inFIG. 5(b) before pattern signal recording. These initial values can beseparately determined from experience, or they can be all set to thesame value. If the same initial value is used for all, the value, forexample, 1 ns, stored for the first pulse movement in a 5S5M pattern inthe left table in FIG. 5(b), for example, is preferably stored for allpatterns. In the case of the right table in FIG. 5(b), the value storedfor 5M5S is used. Note, further, that in this case the value set for the5S5M pattern is determined so that the time between first pulse 401 andmultiple pulse 402 is 0.5T as shown in FIG. 4, and the value set for5M5S is determined so that the time between multiple pulse 403 and lastpulse 404 is 0.5T.

It will also be obvious that the values set for 5S5M and 5M5S can alsobe determined using other methods. An example is shown in FIG. 32.

As shown in FIG. 32, the pattern signal 3201 of the pattern signalgenerator 125 in this example has a single period of 6T. Also shown areoutput signal 3202 from the pulse generator 111; output signal 3203 fromthe pulse moving circuit 110; and marks 3204 formed in the recordingtrack of the optical disc 101 as a result of modulating laser poweroutput between peak power and bias power levels according to outputsignal 3203. It is to be noted that while signals 3201, 3202, and 3203are not generated on the same time base, for convenience they are shownwith corresponding parts in each signal aligned vertically.

The pattern signal 3201 in this case represents marks and spaces with asimple 6T period, and thus contains types 5S5M and 5M5S of the eighteenpattern types shown in FIG. 5(a). The laser is then driven based ondrive signal 3203 in FIG. 32 to record the marks 3204. In this exemplaryembodiment, pattern signal 3201 in FIG. 32 is repeatedly recorded aroundone complete circumference of the recording track. When this track isrecorded, it is then reproduced. Reproduction includes converting anoptical signal from the photodetector 108 to an electrical signal, andthen processing this electrical signal with preamplifier 112, low passfilter 113, and reproduction equalizer 114. The reproduction signal 3205from the reproduction equalizer 114 is applied to asymmetry measuringcircuit 140 and digitizing circuit 115.

The digitizing circuit 115 adjusts the slice level signal 3209 so thatthe output level corresponding to a mark and the output levelcorresponding to a space in the output signal of the digitizing circuitare at equal intervals, and applies this slice level signal 3209 to theasymmetry measuring circuit 140.

The asymmetry measuring circuit 140 compares the average of the high3211 and low 3210 peak values of the reproduction signal 3205 with theslice level signal 3209. When the difference or ratio therebetween isoutside a predetermined range of tolerance, the lengths of the marks3204 and spaces are not equal. This difference is attributable to ashift in the first pulse and last pulse positions. Initial movementvalues 5S5M0 and 5M5S0 are therefore corrected according to the sign ofthe difference so that, for example, the first pulse and last pulse eachmove the same time-base distance in opposite directions. The correctedvalues are then overwritten to memory 129.

It is to be noted that the stored movement values are corrected andoverwritten to 5M5S and 5S5M using a single feedback loop (through 110,109, 108, 112, 115, 140, 129) in the above exemplary embodiment. It willbe obvious, however, that a plurality of feedback loops can bealternatively used. As a result, 5S5M and 5M5S values whereby 6T markscan be recorded at the correct length can be obtained. By thuscorrecting the physical length of a mark used as a reference, marks inother groups can also be recorded at the correct length, and recordingwith less jitter can be achieved.

The options shown in FIG. 38 are now described.

The asymmetry information can likewise be recorded to area 1503 of theoptical disc 1501 shown in FIG. 15 in addition to the optimum or typicalleading and trailing mark edge positions recorded during manufacture.Generally, it is preferable to have a smaller amount of asymmetry value.The optimum asymmetry value slightly varies relatively to differentdiscs due to, e.g., the structure of the recording film of the disc.

For example, in FIG. 32, when the calculated result of:((3215+3214)/2−3216)/(3215−3214)is 1.05 representing the optimum asymmetric value for the disc measured,the calculated value 1.05 or a further modified value of 1.05 is storedso as to enable precise adjustment of the value to be stored in thesettings 5S5M and 5M5S.

The output signal 303 from the pulse moving circuit 110 is input to thelaser drive circuit 109 whereby laser power is modulated so that thelaser emits at peak power while output signal 303 is high, and emits atbias power while the signal is low, to form a mark sequence 304 as shownin FIG. 3.

During reproduction, the collimator lens 104 converts the laser beamemitted from the semiconductor laser 103 to parallel light, which isthen incident on the beam splitter 105. Light passing the beam splitter105 is focused to a light spot by the objective lens 106, and emitted tothe optical disc 101.

Light reflected from the optical disc 101 is then collected by theobjective lens 106, and passed back to the beam splitter 105. Lightreflected by the beam splitter 105 is collected by collective lens 107,and focused on photodetector 108.

The photodetector 108 converts light incident thereon to an electricalsignal, which is then amplified by the preamplifier 112. The outputsignal from the preamplifier 112 is then passed through the low passfilter 113 whereby high frequency signal components are blocked. Thereproduction equalizer 114 then equalizes the signal, which is nextbinarized by the digitizing circuit 115 using a predetermined slicelevel. A reproduction signal 305 converted to a sequence of 0s and 1s isthus output from the digitizing circuit 115 to the pulse position offsetmeasuring circuit 120. The pulse position offset measuring circuit 120measures the interval between specific edges or measures edge intervaljitter; in this exemplary embodiment the pulse position offset measuringcircuit 120 measures the specific edge intervals 321, 322, 323, and 324in the reproduction signal 305.

If the measured edge interval 321 in FIG. 3 is longer than the normal 9Tinterval, the setting for last pulse movement 3M5S in FIG. 5(a) isreduced by the difference between the measured interval 321 and thenormal 9T interval from the current setting of 3M5S0 by way of bus 126.The setting for first pulse movement 5S3M in FIG. 5(a) is similarlyincreased from the current 5S5M0 setting by the difference between theedge interval 322 and the normal 9T interval by way of bus 126 if theedge interval 322 is longer than the normal 9T interval. The valuesstored for 4S5M and 5M4S are likewise corrected based on the measurededge intervals 323 and 324.

When these four settings are updated, the first pattern signal 301 isagain recorded and the edge intervals are measured. This process isrepeated until the difference between the normal interval and themeasured edge interval is below a predetermined threshold levelsimultaneously for all four edge intervals.

When recording the first pattern signal is completed, a second patternsignal is recorded. Shown in FIG. 6 are second pattern signal 601, whichis the output signal from the pattern signal generator 125; outputsignal 602 from the pulse generator 111; output signal 603 from thepulse moving circuit 110; and mark pattern 604 formed in the recordingtrack of the optical disc 101 based on output signal 603. The firstpulse settings 5S4M and 3S5M, and last pulse settings 4M5S and 5M3S inFIG. 5(a) are then updated using the same method described above usingthe first specific pattern signal 301.

When recording the second pattern signal is completed, a third patternsignal is recorded. Shown in FIG. 7 are third pattern signal 701, whichis the output signal from the pattern signal generator 125; outputsignal 702 from the pulse generator 111; output signal 703 from thepulse moving circuit 110; and mark pattern 704 formed in the recordingtrack of the optical disc 101 based on output signal 703.

In FIG. 7 [17, sic], the 10T period of 710 and 711 (a 6T space and 4Tmark) and the 10T period of 712 and 713 (a 4T mark and 6T space [10Tspace, sic]>> 712 is a 4T SPACE and 713 is a 6T MARK in FIG. 7) overlapand appear as a continuous wave. Measured signal 710-711 and the nextmeasured signal 712-713 therefore overlap, and it is difficult toaccurately separate and analyze the measured signals. Utilizing the factthat jitter is minimized if the two 10T periods are substantially thesame length, a jitter meter can therefore be substituted formeasurement. Other than these signal periods, the same method used withthe first pattern is applied to set and update the first pulse settings4S4M and 3S3M, and last pulse settings 4M4S and 3M3S in FIG. 5(a).

The conditions obtaining the least edge jitter with this third patternsignal and the correct edge interval time are the same. For example, ifedge intervals 729 and 730 occur at the correct 9T time interval, jitterat a 9T edge interval will also be the lowest. Therefore, if either edgeinterval is offset from the normal 9T time, jitter at a 9T edge intervalwill increase.

When recording the third pattern signal is completed, a fourth patternsignal is recorded. Shown in FIG. 8 are fourth pattern signal 801, whichis the output signal from the pattern signal generator 125; outputsignal 802 from the pulse generator 111; output signal 803 from thepulse moving circuit 110; and mark pattern 804 formed in the recordingtrack of the optical disc 101 based on output signal 803. The firstpulse setting 4S3M and last pulse setting 4M3S in FIG. 5(a) are updatedusing the same method used with the first pattern signal.

When recording the fourth pattern signal is completed, a fifth patternsignal is recorded. Shown in FIG. 9 are fifth pattern signal 901, whichis the output signal from the pattern signal generator 125; outputsignal 902 from the pulse generator 111; output signal 903 from thepulse moving circuit 110; and mark pattern 904 formed in the recordingtrack of the optical disc 101 based on output signal 903. The firstpulse setting 3S4M and last pulse setting 3M4S in FIG. 5(a) are updatedusing the same method used with the fourth pattern signal.

It is therefore possible with the method according to this preferredembodiment to compensate during recording for the effects of heataccumulation and thermal interference during recording, and thus recorda mark/space pattern with little jitter, by determining before datarecording the mark start position from the length of the recorded markand the length of the space preceding the mark, and determining the markend position from the length of the recorded mark and the length of thespace following thereafter.

It is also possible to determine the optimum mark start and mark endpositions for a specific combination of optical disc and disc recorderbecause the disc recorder performing the actual recording operationdetermines the optimal mark start and edge positions through a testrecording operation.

Furthermore, this preferred embodiment of the present invention recordsfirst through fifth specific test patterns to determine the pulseposition offset whereby edge intervals occur at the correct timeinterval and jitter is minimized. It will be obvious to one withordinary skill in the related art, however, that other specific testpatterns or adjustment methods can be alternatively used insofar as thetest recording enables the mark start and end positions to be determinedaccording to the input signal.

As noted above, the first pulse setting 5S5M and last pulse setting 5M5Sused for marks and spaces of 5T and longer are applicable to all marksbefore pattern signal recording. However, as indicated by the threefirst pulse position settings 5S5M, 4S5M, and 3S5M, the mark length isthe same in each setting and only the length of the preceding spacediffers. There is therefore a simple comparative relationship betweenthe three settings, that is: 5S5M<4S5M<3S5M, or 5S5M>4S5M>3S5M.

FIG. 10 shows marks formed when the first pulse settings are in therelationship 5S5M<4S5M<3S5M. Note that as the space becomes shorter,heat from the preceding mark travels through the space, resulting in theleading edge of the following mark being formed earlier and the lengthof the mark to increase.

FIG. 11 shows marks formed when the last pulse settings are in therelationship 5S5M<4S5M<3S5M. Note that as the space becomes shorter,heat from the following mark travels back through the space to thepreceding mark, thus retarding cooling at the trailing edge of thepreceding mark and resulting in mark elongation.

It should be noted that the direction and degree of change in the markstart and end positions as a result of different space lengths dependson the disc structure and composition of the recording film. However, byusing the above-noted simple relationship between the first and lastpulse settings, it is possible to reduce the number of test recordingsneeded to determine the optimum settings. For example, once the 5S5M and3S5M settings are determined for the first pulse position, the averageof these two settings can be substituted for the initial 4S5M settingused in the test recording sequence for determining the optimum 4S5Msetting.

Once the 5S4M and 4S4M first pulse position settings are determined, itis likewise possible to substitute the 4S4M setting for the initial 3S4Msetting, or if 5S4M<4S4M, for example, to use the difference between4S4M and 5S4M subtracted from the 4S4M setting for the initial 3S4Msetting to reduce the number of test recordings needed to determine theoptimum setting for 3S4M.

It is thus possible to reduce the number of necessary test recordingsneeded to determine the optimum settings by utilizing the verticalrelationship shown in the table in FIG. 5(a) between the settings.

It should be further noted that while the present preferred embodimentof the invention describes shifting the first and last pulse positionsaccording to specific combinations of marks and spaces to be recorded,the present invention shall not be so limited. It is also possible, forexample, to apply the same method of the present invention to optimizepulse width in a recording method in which the first and last pulsewidth is adjusted. This is further described below with reference toFIG. 12.

FIG. 12 is a plan view of an optical disc 1201. In this exemplaryembodiment user data is recorded to data area 1202. Informationindicative of the method used to adjust the first pulse and last pulseaccording to the input data signal is recorded to area 1203 at theinside circumference area of the disc using a sequence of pits and lands(marks and spaces). Between the data area 1202 and adjustment methodrecording area 1203 is a test recording area 1204. Using this discformat, it is possible to determine whether recording is optimized bymoving the first and last pulse positions, or by varying the first andlast pulse width, by reading the adjustment method recording area 1203before starting test recording.

Operation when an optical disc 1301 formatted as shown in FIG. 13 isloaded into a disc recorder as shown in FIG. 1 is described next below.

This optical disc 1301 has a user data area 1302 and an area 1303 forrecording at the time of disc production either an optimized or typicalpulse position value for either the leading or trailing mark edge. Morespecifically, area 1303 records either the first drive pulse position Tuor last drive pulse position Td value. Note further that area 1303 isrecorded at the inside circumference of the disc using a sequence ofpits and lands (marks and spaces).

When this optical disc 1301 is loaded into the disc recorder, theoptical head moves to area 1303 to read the optimum position informationfor the leading and trailing mark edges. The read data signal 128 isthen input to the pulse position setting circuit 129 [NOTE: THIS ISmemory 129 ABOVE], and the optimum position information for the leadingand trailing mark edges is set in the pulse moving circuit 110 via bus126 [sic].

By thus reproducing the leading and trailing mark edge positioninformation optimized for an input signal from area 1303 of the opticaldisc 1301 and setting up the disc recorder for recording based on thisinformation, optimized recording can be achieved with optical discshaving different formats and recording films without first performingthe test recording operation described above.

It will be further obvious that this optimized position informationrecorded to area 1303 need not be obtained for all discs that can beused in the recorder. That is, if the variation between discs issufficiently small, the values obtained for one disc can be prerecordedas typical optimized position information for other discs having thesame format and recording film composition.

FIG. 14 is a plan view of another optical disc 1401. With this disc userdata is recorded to data area 1402. Information indicative of the methodused to adjust the first pulse and last pulse according to the inputdata signal is recorded to area 1403 at the inside circumference area ofthe disc using a sequence of pits and lands (marks and spaces).Recording area 1404 at the inside circumference of the disc is usedduring disc production to record either optimized or typical positioninformation for the first or last mark edge position using a sequence ofpits and lands (marks and spaces). Using this disc format, it ispossible to determine whether recording is optimized by moving the firstand last pulse positions, or by varying the first and last pulse width,by reading area 1403.

It is to be noted that if there are differences in the disc recorderaffecting data recording, for example, variations in the shape of thelight spot incident on the optical disc, the leading and trailing markedge positions needed for optimized recording will also differ. In thiscase the optimized or typical values stored to a particular area of thedisc during disc production can be used as the initial values used in atest recording operation. Compared with starting test recording using auniform default value regardless of differences in disc format andrecording film composition, the number of test patterns recorded and thetime required for determining the optimum mark edge positions for datarecording can be reduced in this case by starting the optimizationoperation with the optimum or typical values prerecorded during discproduction. This is further described below with reference to FIG. 15.

FIG. 15 is a plan view of another optical disc 1501. With this discformat user data is recorded to data area 1502. Recording area 1503 atthe inside circumference of the disc is used during disc production torecord either optimized or typical position information for the first orlast mark edge position using a sequence of pits and lands (marks andspaces). Between the data area 1502 and area 1503 is a test recordingarea 1504. With this format the information recorded to area 1503 isread first and test recording is then performed in area 1504 to recordwith greater optimization than is possible if recording is optimizedusing a single setting.

FIG. 16 is a plan view of yet another optical disc 1601. With this discformat user data is recorded to data area 1602. Information indicativeof the method used to adjust the first pulse and last pulse according tothe input data signal is recorded to area 1603 at the insidecircumference area of the disc using a sequence of pits and lands (marksand spaces). Recording area 1604 at the inside circumference of the discis used during disc production to record either optimized or typicalposition information for the first or last mark edge position using asequence of pits and lands (marks and spaces).

Area 1603 can be read with this disc format to determine whetherrecording is optimized by moving the first and last pulse positions, orby varying the first and last pulse width.

Between the data area 1602 and area 1604 is a test recording area 1605.With this format areas 1603 and 1604 can be read first and testrecording then performed in area 1605 to record with greateroptimization than is possible if recording is optimized using a singlesetting.

Operation when an optical disc 1701 formatted as shown in FIG. 17 isloaded into a disc recorder as shown in FIG. 1 is described next below.

This optical disc 1701 has a user data area 1702 and an area 1703 at theinside circumference of the disc for recording at the time of discproduction either optimized or typical position information (general ordefault) for the first or last mark edge position using a sequence ofpits and lands (marks and spaces). Area 1704 is a test recording area.Area 1705 is used for recording the optimized leading and trailing markedge positions determined by the test recording operation, that is, theresult of the test recording operation.

Further preferably in this case information specific to the discrecorder that performed the test recording is also recorded to area1705. This recorder-specific information typically includes the name ofthe disc recorder manufacturer, product number, where the disc recorderwas manufactured, and the date of manufacture.

By thus recording the optimized results of the test recording andinformation specific to the recorder whereby these optimized recordingvalues are determined to area 1705, this information can be reproducedwhen the optical disc 1701 is subsequently loaded into a disc recorder.If the disc recorder is the same as that by which the information wasrecorded, the optimized leading and trailing mark edge positioninformation can be read directly from disc, and optimized recordingreflecting the specific characteristics of that disc recorder can beachieved without requiring another test recording operation.

It will also be obvious that a plurality of sets of test recordingresults and recorder-specific information can be recorded to area 1705.

Furthermore, when this optical disc 1701 is loaded in a disc recorderfor data recording, area 1705 is reproduced to obtain the specificallyoptimized leading and trailing mark edge position information, and testrecording is then performed in area 1704, the number of signal patternsthat must be repeatedly recorded to determine the optimum edge positionscan be reduced, and the time required for such optimization can bereduced, compared with test recording operations using either a uniqueedge position setting or the mark and space sequence of optimized ortypical leading and trailing mark edge positions prerecorded during discproduction.

FIG. 18 is a plan view of yet another optical disc 1801. This opticaldisc 1801 has a user data area 1802; an area 1803 at the insidecircumference of the disc for recording information indicative of themethod used to adjust the first pulse and last pulse according to theinput data signal using a sequence of pits and lands (marks and spaces);an area 1804 at the inside circumference of the disc for recording atthe time of disc production either optimized or typical positioninformation (general) for the first or last mark edge position using asequence of pits and lands (marks and spaces); a test recording area1805; and an area 1806 for recording the optimized leading and trailingmark edge positions determined by the test recording operation, that is,the result of the test recording operation.

With an optical disc 1801 thus formatted, area 1803 can be read todetermine whether recording is optimized by moving the first and lastpulse positions, or by varying the first and last pulse width.

Further preferably in this case information specific to the discrecorder that performed the test recording is also recorded to area1806. This recorder-specific information typically includes the name ofthe disc recorder manufacturer, product number, where the disc recorderwas manufactured, and the date of manufacture.

By thus recording the optimized results of the test recording andinformation specific to the recorder whereby these optimized recordingvalues are determined to area 1806, this information can be reproducedwhen the optical disc 1801 is subsequently loaded into a disc recorder.If the disc recorder is the same as that by which the information wasrecorded, the optimized leading and trailing mark edge positioninformation can be read directly from disc, and optimized recordingreflecting the specific characteristics of that disc recorder can beachieved without requiring another test recording operation.

It will also be obvious that a plurality of sets of test recordingresults and recorder-specific information can be recorded to area 1806.

The formats of the optical discs shown in FIG. 2 and FIG. 12 throughFIG. 18 are summarized in the table in FIG. 38. Information shown asoptionally added in the table in FIG. 38 is described below.

In addition to optimization method information, area 1203 in opticaldisc 1201 shown in FIG. 12 can store information specific to the opticaldisc 1201, such as the manufacturer's name, product number, date andplace of production, disc format, and recording film composition. Inthis case this disc-specific information and the leading and trailingmark edge position information obtained by test recording are stored tomemory 130 of the disc recorder.

When a new optical disc is loaded, this disc-specific information andmark edge position information is read and stored to memory 130.Disc-specific information and mark edge position information for variousdiscs, that is, discs from different manufacturers and differentversions of a disc, is thus accumulated in memory 130.

When a disc that was previously loaded and recorded to by the discrecorder is again loaded, the disc-specific information is read fromarea 1203 of the loaded disc and used to reference the matchingdisc-specific information in memory 130 to fetch therefrom the matchingspecific mark edge position information. This eliminates the need forrepeatedly recording signal patterns to determine the optimum positioninformation, or reduces the number of test recording operationsrequired, and in both cases shortens the required optimization time.

In addition to the leading and trailing mark edge position information,area 1503 in optical disc 1501 shown in FIG. 15 can store informationspecific to the optical disc 1501, such as the manufacturer's name,product number, date and place of production, disc format, and recordingfilm composition. In this case this disc-specific information and theleading and trailing mark edge position information obtained by testrecording are stored to memory 130 of the disc recorder.

When a disc that was previously loaded and recorded to by the discrecorder is again loaded, the disc-specific information is read fromarea 1503 of the loaded disc and used to reference the matchingdisc-specific information in memory 130 to fetch therefrom the matchingspecific mark edge position information. This eliminates the need forrepeatedly recording signal patterns to determine the optimum positioninformation, or reduces the number of test recording operationsrequired, and in both cases shortens the required optimization time.

In addition to the optimization method information, area 1603 in opticaldisc 1601 shown in FIG. 16 can also store the above-noted informationspecific to the optical disc 1601. In this case this disc-specificinformation and the leading and trailing mark edge position informationobtained by test recording are stored to memory 130 of the discrecorder.

When a disc 1601 that was previously loaded and recorded to by the discrecorder is again loaded, the disc-specific information is read fromarea 1603 of the loaded disc and used to reference the matchingdisc-specific information in memory 130 to fetch therefrom the matchingspecific mark edge position information. Again, this eliminates the needfor repeatedly recording signal patterns to determine the optimumposition information, or reduces the number of test recording operationsrequired, and in both cases shortens the required optimization time.

In addition to the leading and trailing mark edge position information,area 1703 in optical disc 1701 shown in FIG. 17 can also store theabove-noted information specific to the optical disc 1701. In this casethis disc-specific information and the leading and trailing mark edgeposition information obtained by test recording are stored to memory 130of the disc recorder.

When a disc 1701 that was previously loaded and recorded to by the discrecorder is again loaded, the disc-specific information is read fromarea 1703 of the loaded disc and used to reference the matchingdisc-specific information in memory 130 to fetch therefrom the matchingspecific mark edge position information. Again, this eliminates the needfor repeatedly recording signal patterns to determine the optimumposition information, or reduces the number of test recording operationsrequired, and in both cases shortens the required optimization time.

In addition to the optimization method information, area 1803 in opticaldisc 1801 shown in FIG. 18 can also store the above-noted informationspecific to the optical disc 1801. In this case this disc-specificinformation and the leading and trailing mark edge position informationobtained by test recording are stored to memory 130 of the discrecorder.

When a disc 1801 that was previously loaded and recorded to by the discrecorder is again loaded, the disc-specific information is read fromarea 1803 of the loaded disc and used to reference the matchingdisc-specific information in memory 130 to fetch therefrom the matchingspecific mark edge position information. Again, this eliminates the needfor repeatedly recording signal patterns to determine the optimumposition information, or reduces the number of test recording operationsrequired, and in both cases shortens the required optimization time.

A disc format according to this preferred embodiment of the presentinvention is described next with reference to FIG. 34 and FIG. 35. It isto be noted that FIGS. 34 and 35 together show a single disc formattable starting from the pit area and mirror area at the insidecircumference of the disc at the top of the table in FIG. 34 andproceeding to the recording area continuing from FIG. 34 to the outsidecircumference of the disc in FIG. 35.

The pit area comprises an initialization zone and a control data zone onthe outside circumference side of the initialization zone. Theinitialization zone at the inside circumference of the disc prevents theservo from going completely off track if the optical head happens tomove to the inside circumference side of the target address. The controldata zone stores disc-specific information such as the disc type, readpower level, pulse adjustment method, temporary power and operationalpower level information, first and last pulse position information, theoptical disc manufacturer, lot number, and product number. The contentof the control data zone is typically recorded a plurality of times toprevent the disc from becoming unreadable as a result of scratches orsoiling.

The mirror area simply links the pit area with the data recording area.Nothing is recorded to the mirror area and no signals are reproducedtherefrom. It is therefore easy to detect if the optical head passesover the mirror area, and the optical head can therefore be moreaccurately positioned to a specific location on the disc.

The recording area comprises guard track zone 1, disc test zone 1, drivetest zone 1, recorder-specific information recording zone 1, disc errormanagement area 1, the data area, disc error management area 2,recorder-specific information recording zone 2, drive test zone 3, disctest zone 2, and guard track zone 2.

The servo may still be unstable immediately after leaving the mirrorzone. The guard track zone 1 is therefore blank.

The disc test zone 1 is used by the disc manufacturer. The power levelused for recording and the optimum pulse position information aredetermined using this disc test zone 1.

The drive test zone 1 is used by the disc recorder. By separating thedisc test zone and drive test zone, the disc manufacturer can recordother desirable information to the disc test zone.

The recorder-specific information recording zone 1 is the area to whichdata specific to a new disc recorder is recorded each time the disc isloaded into a new disc recorder for recording. When the disc is loadedinto a disc recorder, recorder-specific information 1-n is read from therecorder-specific information recording zone 1 to determine whether dataspecific to that disc recorder is already stored in therecorder-specific information recording zone 1. The recorder-specificinformation of the disc recorder to which the optical disc is loaded isalso contained in memory 130. A CPU (not shown in the figures)controlling the memory 130 can determine whether the samerecorder-specific information is already present.

If the same information has not already been recorded, that is, if thedisc is loaded into a new disc recorder, the recorder-specificinformation, temporary power and operational power level information,and pulse position information are stored as one data set to therecorder-specific information recording zone 1. From several seconds toten several seconds may be required to determine the temporary power andoperational power level information and pulse position information inthis case by means of a test recording operation.

If the same information has already been recorded, that is, if the dischas been previously used in the same disc recorder, the temporary powerand operational power level information and pulse position informationbelonging to the recorder-specific information data set identical to thedata read from the recorder-specific information recording zone 1 isread from memory. This temporary power and operational power levelinformation is then sent to memory 132, and the pulse positioninformation is sent to memory 129. It is to be noted that because thisinformation can be read directly from disc, the several seconds to tenseveral seconds needed for a test recording operation to determine thisinformation can be saved.

If a disc thus formatted is written to by n different disc recorders, nsets of recorder-specific information, temporary power and operationalpower level information, and pulse position information will be recordedto the disc. In a preferred embodiment of the present invention these ndata sets are recorded to a plurality of locations on the disc, such asat the inside circumference and outside circumference of the disc. Bythus recording the data sets to more than one disc location, a scratchor soiling preventing reading the data from one location does notcompletely disable the disc because the data can be read from the otherlocation. It is also possible to record the same information a pluralityof times to the recorder-specific information recording zone 1.

If the recorder-specific information is read and the disc recorderdetermines that the optical disc was previously written to by that discrecorder, the content recorded for the test recording operation can besimplified. Information unique to a particular combination of discrecorder and optical disc is recorded a plurality of times to preventproblems arising from the data becoming unreadable as a result ofscratches or soiling. The recorder-specific information recording zonealso reserves areas for recording this information by a plurality ofdisc recorders. This is because there are minute differences in laserpower in different disc recorders.

The disc error management area 1 is reserved for managing disc errors.

The data area is for recording user data.

Disc error management area 2 is likewise reserved for managing discerrors.

The recorder-specific information recording zone 2 stores the sameinformation stored to recorder-specific information recording zone 1,that is, information unique to a particular combination of optical discand disc recorder by which the optical disc was recorded. By providing arecorder-specific information recording zone at both the insidecircumference and outside circumference sides of a disc, the informationcan be reproduced from one area when it cannot be reproduced from theother area as a result of disc damage or soiling.

The drive test zone 2 is used for test recording by the disc recorder inthe same manner as drive test zone 1. By providing a drive test zone atboth the inside circumference and outside circumference sides of a disc,the information can be reproduced from one area when it cannot bereproduced from the other area as a result of disc damage or soiling. Ifthe disc is greatly warped, it is also possible to perform the testrecording operation at both inside and outside circumference zones tointerpolate the best recording parameters based on a particular radialposition.

The disc test zone 2 is also used for test recording operations by thedisc manufacturer in the same manner as disc test zone 1. By providing adisc test zone at both the inside circumference and outsidecircumference sides of a disc it is possible to determine the effect ofdisc warpage on recording, and use this information as an inspection andshipping standard.

Guard track zone 2 is also blank and is not used for recording. Byproviding guard track zone 2 at the outside circumference edge of thedisc, it is possible to prevent the servo from going completely offtrack if the optical head happens to move beyond the target address.

The above-described disc zones and recording areas are managed usingtheir disc address, which the disc recorder reads and used to determinethe disc layout and zone/area locations.

The relationship between these zones and areas and the areas shown inFIG. 2 and FIGS. 12 to 18 is shown in FIG. 38.

It is to be noted that information specific to the data storage area201, that is, the disc manufacturer, product number, production date andlocation, disc format, and recording film type, can also be recorded tothe optical disc shown in FIG. 2. It will also be obvious that in thiscase the disc-specific information as well as the leading and trailingmark edge position information are stored to memory 130 of the discrecorder.

When a disc that was previously loaded and recorded to by the discrecorder is again loaded, the disc-specific information is read from theloaded disc and used to reference the matching disc-specific informationin memory 130 to fetch therefrom the matching specific mark edgeposition information. This eliminates the need for repeatedly recordingsignal patterns to determine the optimum position information, orreduces the number of test recording operations required, and in bothcases shortens the required optimization time.

It is to be noted that in the above-described preferred embodiments theoptimum leading and trailing mark edge positions are determined by testrecording, but this test recording operation can be preceded by anoperation for optimizing the output power levels, including both peakpower and bias power levels, of the laser beam used for the testrecording operation. The laser power level thus optimized before markedge positions are optimized is referred to herein as the “temporarypower level.” This is in contrast to the operational power level, whichis the laser power level optimized after optimizing the mark edgepositions.

The temporary power level is the power level used to determine theoptimum leading and trailing mark edge positions. The operational powerlevel is the power level used for actual recording in the data area.Variations in laser power from the optimum emission level cause variousproblems. These problems are described below.

The optimum leading and trailing mark edge positions depend on variousoptical disc characteristics as well as the laser power used for testrecording. If laser power changes greatly, the optimum leading andtrailing mark edge positions cannot be determined; even if they aredetermined, recording quality will be poor. The reason for this isdescribed with reference to FIG. 19.

FIG. 19 shows mark shapes and the resulting reproduction signal when a3T signal, that is, the shortest mark length signal, is recorded withdifferent laser power levels. Marks 1901 result from an optimized laserpower setting. Note the mark length and space length are substantiallyequal. The amplitude 1911 of the resulting reproduction signal 1902 istherefore high.

Marks 1903 result from a too-low laser power setting. Note that marklength is shorter than the space length. Because mark and space lengthis not the same, the amplitude 1912 of the resulting reproduction signal1904 is lower than amplitude 1911.

Marks 1905 result when the laser is driven at the power level used toproduce marks 1903 but the emission time is longer than that producingmarks 1903. By thus increasing emission time, mark length and spacelength are made substantially equal, but the mark width is narrower thanthat of marks 1901 formed at the optimized laser power setting. Theamplitude 1913 of the resulting reproduction signal 1906 is thereforelower than amplitude 1911.

Marks 1907 result from a too-high laser power setting. Note that marksare longer than the spaces. Because mark and space length is not thesame, the amplitude 1914 of the resulting reproduction signal 1908 islower than amplitude 1911.

Marks 1909 result when the laser is driven at the power level used toproduce marks 1907 but the emission time is shorter than that producingmarks 1907. By thus decreasing emission time, mark length and spacelength are more nearly equal, but the high laser power setting preventsformation of equal length marks and spaces. The amplitude 1915 of theresulting reproduction signal 1910 is therefore lower than amplitude1911.

It will thus be obvious that when laser power is low, the resultingmarks cannot be formed with sufficient width, and when laser power ishigh the marks and spaces cannot be formed with the same length. As aresult it may not be possible to achieve optimal recording results. Bydetermining the best laser power setting before the test recordingoperation for determining the best leading and trailing mark edgepositions, optimized data recording can be more reliably achieved.

It is necessary to determine both the peak and bias power levels. Apreferred method for determining the peak power level is described firstbelow.

When a optical disc 101 is loaded, the optical head moves to writingtest zone 202 for determining the best power level. Switch 121 isconductive through contacts 122 and 124 at this time.

The power level setting circuit 119 first sets the default peak and biaspower levels to the laser drive circuit 109. The output signal fromunique pattern generator 127 a of the recording data generator 127 isthen modulated by the modulation circuit 126, and passed through switch121 to the pulse generator 111 for conversion to a pulse signal. Thispulse signal is then passed through delay circuit 138 to the pulsemoving circuit 110 from which a signal in which the leading and trailingpulse edges are shifted is output.

Signal patterns output from the modulation circuit 126 are shown in FIG.20. These signal patterns can be prestored to the optical disc or in thedisc recorder.

FIG. 20(a) shows the sector format of the optical disc 101, comprising adata storage area 201, writing test zone 202, track 2001, addresses 2002and 2003, and sectors 2004.

The format of sectors 2004 is shown in FIG. 20(b). Each sector 2004comprises main data 2006 and a VFO signal 2005 for PLL 116synchronization (see FIG. 1). The VFO signal has a simple 4T period.

The main data 2006 comprises a plurality of frames 2007, 2008, 2009.Each frame comprises a synchronization mark for synchronizing the startof data reproduction, a DSV compensation pattern 2011 for resetting theDSV to 0, and a simple 3T pattern signal 2012. Note that the DSV is thedifference of marks and spaces within a specific period in the syncmark. A typical 3T pattern signal 2012 is shown in FIG. 20(c). Note thatby resetting the DSV of the recording signal pattern to 0, the DSVcompensation pattern 2011 enables the signal pattern to be correctlydigitized during reproduction.

It is to be noted that while simple 3T pattern signals are frequentlyused in this exemplary embodiment of the invention, a 4T or otherpattern signal can be used in place of the 3T pattern signal 2012insofar as the signal has a simple repeating pattern. By recording sucha simple pattern signal, an appropriate laser power setting can bedetermined even when the optimum leading and trailing mark edgepositions are not yet determined and recording quality will therefore below using a random pattern signal. Note, further, that the memoryrequired for data comparator 131 can be reduced by comparing signalsbefore and after modulation.

If a 4T pattern signal is used in place of a 3T pattern signal 2012, theVFO signal will also have a 4T period, thereby preventing asymmetrybetween the VFO signal part and the main data, and enabling moreaccurate digitization.

It is to be noted that while signals containing a simple 3T pattern arefrequently used in this exemplary embodiment, patterns comprising signalgroups contained in a signal type having the same optimum adjustment ofleading and trailing mark edge positions cam be alternatively used. Byrecording signal groups from the same signal type, an appropriate laserpower setting can be determined even when the optimum leading andtrailing mark edge positions are not yet determined and recordingquality will therefore be low using a random pattern signal containingall signal types.

The output signal from pulse moving circuit 110 is input to the laserdrive circuit 109, which drives the semiconductor laser to emit at peakand bias power levels according to this output signal and thereby form asequence of marks on the disc.

When recording ends the mark sequence is reproduced, and the outputsignal from demodulation circuit 117 is input to the data comparator131. The output signal from unique pattern generator 127 a is also inputto data comparator 131. The data comparator 131 thus compares therecording data and the reproduced data and detects, for example, a byteerror rate (BER).

FIG. 21 shows the relationship between peak power and BER. Peak power ison the X axis and BER on the Y axis in FIG. 21. If reproductionconditions are equal, a low BER generally indicates more accuraterecording. Bias power is therefore fixed and the peak power varied whilethis record and reproduce loop is repeated to find the peak power 2102(typically approximately 8 mW) at which the BER reaches a specificthreshold value. A predefined margin is then added to this peak power2102 level to set the peak power level, typically approximately 10 mW.It is to be noted that by appropriately controlling this added marginthe peak power level can be optimized for the test recording operationdetermining the optimum leading and trailing mark edge positions. Note,further, that this margin can be applied to the peak power levelobtaining a BER of a particular threshold value by multiplying the peakpower level by a margin constant (such as 1.2) or adding thereto amargin constant such as 2 mW.

A method for determining bias power is described next. The peak powersetting determined by the power level setting circuit 119 as describedabove and the initial bias power setting are first set to the laserdrive circuit 109. The modulation circuit 126 then outputs a randomsignal according to the random pattern signal from the random patterngenerator 127 b of the recording data generator 127, and the pattern isrecorded using the above power settings. The modulation circuit 126 thengenerates a signal containing many 3T patterns according to a signalfrom the unique pattern generator 127 a of the recording data generator127, and this pattern is recorded using the above power settings.

When recording ends the mark sequence is reproduced, and the outputsignal from demodulation circuit 117 is input to the data comparator131. The output signal from recording data generator 127 is also inputto data comparator 131. The data comparator 131 thus compares therecording data and the reproduced data and detects, for example, a byteerror rate (BER).

FIG. 22 shows the relationship between bias power and BER. Bias power ison the X axis and BER on the Y axis in FIG. 22. If reproductionconditions are equal, a low BER generally indicates more accuraterecording. Peak power is therefore fixed and the bias power varied whilethis record and reproduce loop is repeated to find the low 2202 and high2203 bias power settings at which the BER reaches a specific thresholdvalue. Note that these low and high bias power settings are typicallyapproximately 3 mW and 7 mW, respectively. The average, 5 mW in thiscase, between these low and high bias power levels is then used as thebias power level for test recording obtaining the optimum leading andtrailing mark edge positions.

A further method for determining the bias power setting is describednext with reference to FIG. 23. In this method a signal containing manysimple 3T patterns is recorded after recording a random signal and theBER is detected. A random signal is then recorded again, a signalcontaining many simple 11T patterns is recorded, and the BER isdetected. The high and low bias power levels are then determined for the3T pattern signal and the 11T pattern signal, and the average of thegreater of the two low settings, level 2302 in this case, and the lesserof the two high settings, level 2303 in this case, is obtained and usedas the bias power level for test recording obtaining the optimum leadingand trailing mark edge positions.

When there is a difference between the bias power range at which the BERis a specific threshold value or less when the 3T signal having theshortest interval is recorded, and the bias power range at which the BERis a specific threshold value or less when the 11T signal having thelongest interval is recorded, the bias power level can be moreappropriately set by using the average of the ranges in which both arebelow this threshold value.

It is therefore possible as described above to achieve more accuraterecording by determining an optimum emission power level for the testrecording operation before performing the test recording operation todetermine the optimum leading and trailing mark edge positions.

It will also be obvious that by the disc recorder that actually recordsthe leading and trailing mark edge determining the best laser powersettings through test recording to the actual disc to be used forrecording, recording optimized for a specific combination of discrecorder and a specific optical disc can be achieved.

It will yet further be obvious that while this preferred embodiment ofthe present invention detects the BER as a means of detectingreproduction signal quality, the present invention shall not be solimited and various other methods of detecting reproduction signalquality, such as by detecting the jitter, can be alternatively used.

Another method of determining the peak power level is described belowwith reference to FIG. 36. This method detects asymmetry using a simple6T pattern signal. Shown in FIG. 36 are the 6T pattern signal 3601output from pattern signal generator 125; the output signal 3602 of thepulse generator 111; output signal 3603 from pulse moving circuit 110;and the mark pattern 3604 formed in the track on optical disc 101 bymodulating laser output between peak and bias power levels according tosignal 3603. It is to be noted that while signals 3601, 3602, and 3603are not generated on the same time base, for convenience they are shownwith corresponding parts in each signal aligned vertically.

The pattern signal in this case represents marks and spaces with asimple 6T period, and thus contains types 5S5M and 5M5S of the eighteenpattern types shown in FIG. 5(a). The laser is then driven based ondrive signal 3603 in FIG. 36 to record the marks 3604. In this exemplaryembodiment, pattern signal 3601 in FIG. 36 is repeatedly recorded aroundone complete circumference of the recording track. When this track isrecorded, it is then reproduced. Reproduction includes converting anoptical signal from the photodetector 108 to an electrical signal, andthen processing this electrical signal with preamplifier 112, low passfilter 113, and reproduction equalizer 114. The reproduction signal 3605from the reproduction equalizer 114 is applied to asymmetry measuringcircuit 140 and digitizing circuit 115.

The digitizing circuit 115 adjusts the slice level signal 3609 so thatthe output level corresponding to a mark and the output levelcorresponding to a space in the output signal of the digitizing circuitare at equal intervals, and applies this slice level signal 3609 to theasymmetry measuring circuit 140.

The asymmetry measuring circuit 140 compares the average of the high3611 and low 3610 peak values of the reproduction signal 3605 with theslice level signal 3609 [3612, sic]. When the difference or ratiotherebetween is outside a specified range, the peak power setting isoff. The peak power setting is therefore adjusted according to the signof this difference or ratio. This 6T pattern signal recording,reproduction, and asymmetry measurement loop is then repeated until thedetected asymmetry is within a specific range.

The options shown in FIG. 38 are described further below.

In addition to the optimum or typical leading and trailing mark edgepositions recorded to area 1503 of the optical disc 1501 shown in FIG.15 during manufacture, the temporary power level information used foradjusting the leading and trailing mark edge positions can be recorded.Note that this temporary power level information includes the peakpower, bias power, margin constant, and asymmetry information. It isalso possible to record all or just part of this temporary power levelinformation. This is also true of the other optical discs describedbelow.

When this optical disc is loaded, area 1503 is read to obtain thetemporary power level information. Test recording is then performed todetermine the specific bias power level. The ratio between the typicalpeak and bias power level information read from area 1503 is thenobtained. This ratio can then be multiplied with the specific bias powerlevel obtained by test recording to obtain the specific peak powersetting. It is to be noted that the specific bias power level isobtained through test recording to compensate for deterioration of thelaser, lens fogging, and other factors causing a loss of laser power.Test recording for determining the specific peak power setting cantherefore be omitted, and the time required to determine the conditionsfor optimized recording can be shortened.

It will be obvious that if there is no variation in laser power, thetypical peak and bias power values read from area 1503 can be used asread.

In addition, when the peak power level is obtained by detectingasymmetry, less asymmetry is generally better but the optimum asymmetrysetting will vary slightly according to such factors as the recordingfilm composition.

Referring to FIG. 36 for example, if peak power is optimal when thecalculated result of ((3615+3614)/2−3616)/(3615−3614) is 1.05, a moreprecise peak power setting can be obtained by recording this optimalasymmetry value (that is, either 1.05 or the result of a specificoperation applied to 1.05) to disc.

Furthermore, when the peak power level is obtained by detecting the BER,the optimum margin added will vary slightly according to such factors asthe recording film composition. For example, if the optimum peak poweris the value at 1.2 times the threshold value, a more precise peak powersetting can be obtained by recording this optimal margin (that is, 1.2or the result of a specific operation applied to 1.2) to disc.

In addition to the optimum or typical leading and trailing mark edgepositions recorded to area 1604 of the optical disc 1601 shown in FIG.16 during manufacture, the temporary power level information used foradjusting the leading and trailing mark edge positions can be recorded.Note that this temporary power level information includes the peakpower, bias power, margin constant, and asymmetry information.

When this optical disc is loaded, area 1604 is read to obtain thetemporary power level information. Test recording is then performed todetermine the specific bias power level. The ratio between the typicalpeak and bias power level information read from area 1604 is thenobtained. This ratio can then be multiplied with the specific bias powerlevel obtained by test recording to obtain the specific peak powersetting. Test recording for determining the specific peak power settingcan therefore be omitted, and the time required to determine theconditions for optimized recording can be shortened.

It will be obvious that if there is no variation in laser power, thetypical peak and bias power values read from area 1604 can be used asread.

In addition, when the peak power level is obtained by detectingasymmetry, less asymmetry is generally better but the optimum asymmetrysetting will vary slightly according to such factors as the recordingfilm composition.

Referring to FIG. 36 for example, if peak power is optimal when thecalculated result of ((3615+3614)/2−3616)/(3615−3614) is 1.05, a moreprecise peak power setting can be obtained by recording this optimalasymmetry value (that is, either 1.05 or the result of a specificoperation applied to 1.05) to disc.

Furthermore, when the peak power level is obtained by detecting the BER,the optimum margin added will vary slightly according to such factors asthe recording film composition. For example, if the optimum peak poweris the value at 1.2 times the threshold value, a more precise peak powersetting can be obtained by recording this optimal margin (that is, 1.2or the result of a specific operation applied to 1.2) to disc.

In addition to the optimum or typical leading and trailing mark edgepositions recorded to area 1703 of the optical disc 1701 shown in FIG.17 during manufacture, the temporary power level information used foradjusting the leading and trailing mark edge positions can be recorded.Note that this temporary power level information includes the peakpower, bias power, margin constant, and asymmetry information.

When this optical disc is loaded, area 1703 is read to obtain thetemporary power level information. Test recording is then performed todetermine the specific bias power level. The ratio between the typicalpeak and bias power level information read from area 1703 is thenobtained. This ratio can then be multiplied with the specific bias powerlevel obtained by test recording to obtain the specific peak powersetting. Test recording for determining the specific peak power settingcan therefore be omitted, and the time required to determine theconditions for optimized recording can be shortened.

It will be obvious that if there is no variation in laser power, thetypical peak and bias power values read from area 1703 can be used asread.

In addition, when the peak power level is obtained by detectingasymmetry, less asymmetry is generally better but the optimum asymmetrysetting will vary slightly according to such factors as the recordingfilm composition.

Referring to FIG. 36 for example, if peak power is optimal when thecalculated result of ((3615+3614)/2−3616)/(3615−3614) is 1.05, a moreprecise peak power setting can be obtained by recording this optimalasymmetry value (that is, either 1.05 or the result of a specificoperation applied to 1.05) to disc.

Furthermore, when the peak power level is obtained by detecting the BER,the optimum margin added will vary slightly according to such factors asthe recording film composition. For example, if the optimum peak poweris the value at 1.2 times the threshold value, a more precise peak powersetting can be obtained by recording this optimal margin (that is, 1.2or the result of a specific operation applied to 1.2) to disc.

In addition to the leading and trailing mark edge positions determinedby test recording and recorded to area 1705 of the optical disc 1701shown in FIG. 17, the temporary power level information used foradjusting the leading and trailing mark edge positions can be recorded.Note that this temporary power level information includes the specificpeak power, specific bias power, margin constant, and asymmetryinformation.

When this optical disc is again loaded into the same disc recorder, area1705 is read to obtain specific temporary power level information, suchas the specific bias power setting. If the specific bias power settingis the same as the typical bias power setting recorded to area 1705,test recording for determining the specific peak power setting and theoptimum leading and trailing mark edge positions can therefore beomitted, and the time required to determine the conditions for optimizedrecording can be shortened.

It is also possible in this case to quickly obtain the optimum temporarypower setting using the information recorded to area 1705 when themargin constant, asymmetry information, and other temporary powerinformation recorded to area 1703 is unreadable due to a disc error,soiling, or other problem.

In addition to the optimum or typical leading and trailing mark edgepositions recorded to area 1804 of the optical disc 1801 shown in FIG.18 during manufacture, the temporary power level information used foradjusting the leading and trailing mark edge positions can be recorded.Note that this temporary power level information includes the peakpower, bias power, margin constant, and asymmetry information.

When this optical disc is loaded, area 1804 is read to obtain thetemporary power level information. Test recording is then performed todetermine the specific bias power level. The ratio between the typicalpeak and bias power level information read from area 1804 is thenobtained. This ratio can then be multiplied with the specific bias powerlevel obtained by test recording to obtain the specific peak powersetting. Test recording for determining the specific peak power settingcan therefore be omitted, and the time required to determine theconditions for optimized recording can be shortened.

It will be obvious that if there is no variation in laser power, thetypical peak and bias power values read from area 1804 can be used asread.

In addition, when the peak power level is obtained by detectingasymmetry, less asymmetry is generally better but the optimum asymmetrysetting will vary slightly according to such factors as the recordingfilm composition.

Referring to FIG. 36 for example, if peak power is optimal when thecalculated result of ((3615+3614)/2−3616)/(3615−3614) is 1.05, a moreprecise peak power setting can be obtained by recording this optimalasymmetry value (that is, either 1.05 or the result of a specificoperation applied to 1.05) to disc.

Furthermore, when the peak power level is obtained by detecting the BER,the optimum margin added will vary slightly according to such factors asthe recording film composition. For example, if the optimum peak poweris the value at 1.2 times the threshold value, a more precise peak powersetting can be obtained by recording this optimal margin (that is, 1.2or the result of a specific operation applied to 1.2) to disc.

In addition to the leading and trailing mark edge positions determinedby test recording and recorded to area 1806 of the optical disc 1801shown in FIG. 18, the temporary power level information used foradjusting the leading and trailing mark edge positions can be recorded.Note that this temporary power level information includes the specificpeak power, specific bias power, margin constant, and asymmetryinformation.

When this optical disc is again loaded into the same disc recorder, area1806 is read to obtain specific temporary power level information, suchas the specific bias power setting. If the specific bias power settingis the same as the typical bias power setting recorded to area 1806,test recording for determining the specific peak power setting andadjusting leading and trailing mark edge positions according to the datacan therefore be omitted, and the time required to determine theconditions for optimized recording can be shortened.

It is also possible in this case to quickly obtain the optimum temporarypower setting using the information recorded to area 1806 [1805, sic]when the margin constant, asymmetry information; and other temporarypower information recorded to area 1803 is unreadable due to a discerror, soiling, or other problem.

If information specific to the optical disc 1201, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1203 of the optical disc 1201shown in FIG. 12 in addition to the adjustment method information, thisdisc-specific information and the temporary power level information(such as peak power, bias power, margin constant, asymmetry information)used for adjusting the leading and trailing mark edge positions can bestored to memory 130 of the disc recorder.

When this optical disc is then loaded, area 1203 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the typical peak and bias power levelinformation in memory 130 is then obtained. This ratio can then bemultiplied with the specific bias power level obtained by test recordingto obtain the specific peak power setting. Test recording fordetermining the specific peak power setting can therefore be omitted,and the time required to determine the conditions for optimizedrecording can be shortened.

If information specific to the optical disc 1501, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1503 of the optical disc 1501shown in FIG. 15 in addition to the leading and trailing mark edgeposition information, this disc-specific information and the temporarypower level information (such as peak power, bias power, marginconstant, asymmetry information) used for adjusting the leading andtrailing mark edge positions can be stored to memory 130 of the discrecorder.

When this optical disc is then loaded, area 1503 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the typical peak and bias power levelinformation in memory 130 is then obtained. This ratio can then bemultiplied with the specific bias power level obtained by test recordingto obtain the specific peak power setting. Test recording fordetermining the specific peak power setting can therefore be omitted,and the time required to determine the conditions for optimizedrecording can be shortened.

In addition, if the margin constant, asymmetry information, or othertemporary power level information cannot be read from area 1503 becauseof a disc error or soiling, the optimum temporary power level can stillbe quickly obtained because this unreadable information is in memory130.

If information specific to the optical disc 1601, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1603 of the optical disc 1601shown in FIG. 16 in addition to the adjustment method information, thisdisc-specific information and the temporary power level information(such as peak power, bias power, margin constant, asymmetry information)used for adjusting the leading and trailing mark edge positions can bestored to memory 130 of the disc recorder. When this optical disc isthen loaded, area 1603 is read to detect whether the disc-specificinformation is already in memory 130. If it is, test recording is thenperformed to determine the specific bias power level. The ratio betweenthe typical peak and bias power level information in memory 130 is thenobtained. This ratio can then be multiplied with the specific bias powerlevel obtained by test recording to obtain the specific peak powersetting. Test recording for determining the specific peak power settingcan therefore be omitted, and the time required to determine theconditions for optimized recording can be shortened.

In addition, if the margin constant, asymmetry information, or othertemporary power level information cannot be read from area 1603 becauseof a disc error or soiling, the optimum temporary power level can stillbe quickly obtained because this unreadable information is in memory130.

If information specific to the optical disc 1701, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1703 of the optical disc 1701shown in FIG. 17 in addition to the leading and trailing mark edgeposition information, this disc-specific information and the temporarypower level information (such as peak power, bias power, marginconstant, asymmetry information) used for adjusting the leading andtrailing mark edge positions can be stored to memory 130 of the discrecorder.

When this optical disc is then loaded, area 1703 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the typical peak and bias power levelinformation in memory 130 is then obtained. This ratio can then bemultiplied with the specific bias power level obtained by test recordingto obtain the specific peak power setting. Test recording fordetermining the specific peak power setting can therefore be omitted,and the time required to determine the conditions for optimizedrecording can be shortened.

In addition, if the margin constant, asymmetry information, or othertemporary power level information cannot be read from area 1703 or 1705because of a disc error or soiling, the optimum temporary power levelcan still be quickly obtained because this unreadable information is inmemory 130.

In addition, if area 1705 is overwritten by a different disc recorder,the optimum temporary power level setting can be obtained quickly byreading the information from memory 130.

If information specific to the optical disc 1801, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1803 of the optical disc 1801shown in FIG. 18 in addition to the adjustment method information, thisdisc-specific information and the temporary power level information(such as peak power, bias power, margin constant, asymmetry information)used for adjusting the leading and trailing mark edge positions can bestored to memory 130 of the disc recorder.

When this optical disc is then loaded, area 1803 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the typical peak and bias power levelinformation in memory 130 is then obtained. This ratio can then bemultiplied with the specific bias power level obtained by test recordingto obtain the specific peak power setting. Test recording fordetermining the specific peak power setting can therefore be omitted,and the time required to determine the conditions for optimizedrecording can be shortened.

In addition, if the margin constant, asymmetry information, or othertemporary power level information cannot be read from area 1803 or 1805because of a disc error or soiling, the optimum temporary power levelcan still be quickly obtained because this unreadable information is inmemory 130.

In addition, if area 1805 is overwritten by a different disc recorder,the optimum temporary power level setting can be obtained quickly byreading the information from memory 130.

It is to be noted that while the specific peak power setting isdetermined in this exemplary embodiment after determining the specificbias power setting, it is also possible to determine the specific peakpower setting first and then the specific bias power setting.

Furthermore, the optimum leading and trailing mark edge positions aredetermined by test recording to a specific area as described above. Itis alternatively possible, however, to determine the above specific biasand peak power settings, and then determine the operational power levelsetting for the laser beam used for data recording.

Referring to FIG. 5(a), for example, if the setting for the first pulseposition 3S5M or last pulse position 3S5M differs greatly from theinitial value for determining the peak power of the temporary powerlevel, the margin used to determine the peak power may be low. Forexample, while the disc can normally be recorded properly even when theeffective temporary power level drops 2 mW if the disc area to bewritten is soiled, it may not be possible to record correctly when thereis only a 1 mW drop if the margin is too low.

By setting the operational power level, however, a more reliable powermargin can be assured for optimized recording.

While it is necessary to determine both the peak and bias power levels,a preferred method for determining the peak power level is describedfirst below. In this case, switch 121 is conductive through contacts 122and 124.

The power level setting circuit 119 first sets the default peak and biaspower levels to the laser drive circuit 109 based on data read frommemory 132. The output signal from random pattern generator 127 b of therecording data generator 127 is then modulated by the modulation circuit126, and passed through switch 121 to the pulse generator 111 forconversion to a pulse signal. This pulse signal is then passed to thepulse moving circuit 110 from which a signal in which the leading andtrailing pulse edges are shifted is output.

It is to be noted that the signal output from modulation circuit 126 isa random signal in which the DSV is 0.

The output signal from pulse moving circuit 110 is input to the laserdrive circuit 109, which drives the semiconductor laser to emit at peakand bias power levels according to this output signal and thereby form asequence of marks on the disc.

When recording ends the mark sequence is reproduced, and the outputsignal from demodulation circuit 117 is input to the data comparator131. The output signal from random pattern generator 127 b is also inputto data comparator 131. The data comparator 131 thus compares therecording data and the reproduced data and detects, for example, a byteerror rate (BER).

FIG. 24 shows the relationship between peak power and BER. Peak power ison the X axis and BER on the Y axis in FIG. 24. If reproductionconditions are equal, a low BER generally indicates more accuraterecording. Bias power is therefore fixed and the peak power varied whilethis record and reproduce loop is repeated to find the peak power 2402(typically approximately 8 mW) at which the BER reaches a specificthreshold value. A predefined margin is then added to this peak power2402 level to set the peak power level, typically approximately 10 mW.It is to be noted that by appropriately controlling this added marginthe peak power level can be optimized for data recording. Note, further,that this margin can be applied to the peak power level obtaining a BERof a particular threshold value by multiplying the peak power level by aconstant factor (such as 1.2) or adding thereto a constant such as 2 mW.

A method for determining bias power is described next. The peak powersetting determined by the power level setting circuit 119 as describedabove and the initial bias power setting are first set to the laserdrive circuit 109. The modulation circuit 126 then outputs a randomsignal according to the random pattern signal from the random patterngenerator 127 b, and the pattern is recorded using the above powersettings.

When recording ends the mark sequence is reproduced, and the outputsignal from demodulation circuit 117 is input to the data comparator131. The output signal from random pattern generator 127 b is also inputto data comparator 131. The data comparator 131 thus compares therecording data and the reproduced data and detects, for example, a byteerror rate (BER).

FIG. 25 shows the relationship between bias power and BER. Bias power ison the X axis and BER on the Y axis in FIG. 25. If reproductionconditions are equal, a low BER generally indicates more accuraterecording. Peak power is therefore fixed and the bias power varied whilethis record and reproduce loop is repeated to find the low 2502 and high2503 bias power settings at which the BER reaches a specific thresholdvalue. Note that these low and high bias power settings are typicallyapproximately 3 mW and 7 mW, respectively. The average, 5 mW in thiscase, between these low and high bias power levels is then used as thebias power level for test recording obtaining the optimum leading andtrailing mark edge positions.

It is therefore possible as described above to achieve more accuraterecording by determining an optimum emission power level for datarecording operation after determining the optimum leading and trailingmark edge positions.

It will also be obvious that by the disc recorder that actually recordsthe leading and trailing mark edge determining the best laser powersettings through test recording to the actual disc to be used forrecording, recording optimized for a specific combination of discrecorder and a specific optical disc can be achieved.

It will yet further be obvious that while this preferred embodiment ofthe present invention detects the BER as a means of detectingreproduction signal quality, the present invention shall not be solimited and various other methods of detecting reproduction signalquality, such as by detecting the jitter, can be alternatively used.

The options shown in FIG. 38 are described yet further below.

In addition to the optimum or typical leading and trailing mark edgepositions recorded to area 1503 of the optical disc 1501 shown in FIG.15 during manufacture, the operational power level information can berecorded. Note that this operational power level information includesthe peak power, bias power, and margin constant. It is also possible torecord all or just part of this operational power level information.This is also true of the other optical discs described below.

When this optical disc is loaded, area 1503 is read to obtain theoperational power level information. Test recording is then performed todetermine the specific bias power level. The ratio between the typicalpeak and bias power level information read from area 1503 is thenobtained. This ratio can then be multiplied with the specific bias powerlevel obtained by test recording to obtain the optimum specific peakpower setting. Test recording for determining the specific peak powersetting can therefore be omitted, and the time required to determine theconditions for optimized recording can be shortened.

It will be obvious that if there is no variation in laser power, thetypical peak and bias power values read from area 1503 can be used asread.

Furthermore, when the peak power level is obtained by detecting the BER,the optimum margin added will vary slightly according to such factors asthe recording film composition. For example, if the optimum peak poweris the value at 1.2 times the threshold value, a more precise peak powersetting can be obtained by recording this optimal margin (that is, 1.2or the result of a specific operation applied to 1.2) to disc.

It should be further noted that if the operational power levelinformation for adjusting the leading and trailing mark edge positionsis not recorded to area 1503, the temporary power level information canbe used. Conversely, the operational power level information can be usedto obtain the temporary power level.

The operational power level information can likewise be recorded to area1604 of the optical disc 1601 shown in FIG. 16 in addition to theoptimum or typical leading and trailing mark edge positions recordedduring manufacture.

When this optical disc is loaded, area 1604 is read to obtain theoperational power level information. To determine the specific biaspower level, for example, the ratio between the typical peak and biaspower level information read from area 1604 is then obtained. After thespecific peak power is determined, this ratio can be multiplied with thespecific peak power to predict the optimum specific bias power setting.Test recording for determining the specific bias power setting cantherefore be omitted, and the time required to determine the conditionsfor optimized recording can be shortened.

It is to be noted that if the power level information for adjusting theleading and trailing mark edge positions is not recorded to area 1604,the optimum bias power setting before edge position adjustment can bepredicted by determining the power level information after edge positionadjustment. For example, to determine the bias power setting before edgeposition adjustment, the pre-adjustment peak power setting isdetermined, the ratio between the peak power and bias power determinedafter such adjustment and recorded to area 1604 is calculated, and thisratio is then applied to the pre-adjustment peak power setting topredict the optimum bias power setting before edge position adjustment.

The operational power level information can likewise be recorded to area1703 of the optical disc 1701 shown in FIG. 17 in addition to theoptimum or typical leading and trailing mark edge positions recordedduring manufacture.

When this optical disc is loaded, area 1703 is read to obtain theoperational power level information. Bias power is then determinedthrough test recording, the ratio between the peak and bias power valuesread from area 1703 is then calculated, and this ratio is multiplied bythe bias power value obtained from test recording to obtain the optimumpeak power setting. Test recording for determining the specific peakpower setting can therefore be omitted, and the time required todetermine the conditions for optimized recording can be shortened.

It should be further noted that if the temporary power level informationfor adjusting the leading and trailing mark edge positions is notrecorded to area 1703, the operational power level information can beused. First, the operational power setting recorded to area 1703 isread. The bias power setting of the temporary power level information isthen obtained by test recording, and the ratio between the peak and biaspower settings of the operational power level setting is calculated. Theoptimum peak power level of the temporary power level information canthen be calculated by multiplying this ratio with the bias power settingof the temporary power level information. Test recording for determiningthe specific peak power setting of the temporary power level cantherefore be omitted, and the time required to determine the conditionsfor optimized recording can be shortened.

The operational power level information can likewise be recorded to area1705 of the optical disc 1701 shown in FIG. 17 in addition to theleading and trailing mark edge positions determined by test recording.

In this case, when the optical disc is loaded to a disc recorder forrecording, area 1705 is read to obtain the temporary power levelinformation. If the bias power setting determined through test recordingis the same as the bias power setting recorded to area 1705, subsequenttest recording for determining the specific peak power setting can beomitted, and the time required to determine the conditions for optimizedrecording can be shortened.

The operational power level information can likewise be recorded to area1804 of the optical disc 1801 shown in FIG. 18 in addition to theoptimum or typical leading and trailing mark edge positions recordedduring manufacture.

When this optical disc is loaded, area 1804 is read to obtain theoperational power level information. Bias power is then determinedthrough test recording, the ratio between the peak and bias power valuesread from area 1804 is then calculated, and this ratio is multiplied bythe bias power value obtained from test recording to obtain the optimumpeak power setting. Test recording for determining the specific peakpower setting can therefore be omitted, and the time required todetermine the conditions for optimized recording can be shortened.

It should be further noted that if the temporary power level informationfor adjusting the leading and trailing mark edge positions is notrecorded to area 1804, the operational power level information can beused. First, the operational power setting recorded to area 1804 isread. The bias power setting of the temporary power level information isthen obtained by test recording, and the ratio between the peak and biaspower settings of the operational power level setting is calculated. Theoptimum peak power level of the temporary power level information canthen be calculated by multiplying this ratio with the bias power settingof the temporary power level information. Test recording for determiningthe specific peak power setting of the temporary power level cantherefore be omitted, and the time required to determine the conditionsfor optimized recording can be shortened.

The operational power level information can likewise be recorded to area1806 of the optical disc 1801 shown in FIG. 18 in addition to theleading and trailing mark edge positions determined by test recording.

In this case, when the optical disc is next loaded to a disc recorderfor recording, area 1806 is read to obtain the temporary power levelinformation. If the bias power setting determined through test recordingis the same as the bias power setting recorded to area 1806, subsequenttest recording for determining the specific peak power setting can beomitted, and the time required to determine the conditions for optimizedrecording can be shortened.

It is to be noted that while the specific peak power is determined afterdetecting the specific bias power setting in this exemplary embodiment,it is alternatively possible to determine the specific peak powersetting and then the specific bias power setting.

If information specific to the optical disc 1201, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1203 of the optical disc 1201shown in FIG. 12 in addition to the adjustment method information, thisdisc-specific information and the operational power level information(such as peak power, bias power, margin constant) used for adjusting theleading and trailing mark edge positions can be stored to memory 130 ofthe disc recorder.

When this optical disc is then loaded, area 1203 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the peak and bias power level informationin memory 130 is then obtained. This ratio can then be multiplied withthe specific bias power level obtained by test recording to obtain thespecific peak power setting. Test recording for determining the specificpeak power setting can therefore be omitted, and the time required todetermine the conditions for optimized recording can be shortened.

If the temporary power level information for adjusting the leading andtrailing mark edge positions is not recorded to memory 130, theoperational power level information can be used. First, the operationalpower setting recorded to area 1203 is read. The bias power setting ofthe temporary power level information is then obtained by testrecording, and the ratio between the peak and bias power settings of theoperational power level setting is calculated. The optimum peak powerlevel of the temporary power level information can then be calculated bymultiplying this ratio with the bias power setting of the temporarypower level information. Test recording for determining the specificpeak power setting of the temporary power level can therefore beomitted, and the time required to determine the conditions for optimizedrecording can be shortened.

If information specific to the optical disc 1601, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1603 of the optical disc 1601shown in FIG. 16 in addition to the adjustment method information, thisdisc-specific information and the operational power level information(such as peak power, bias power, margin constant) used for adjusting theleading and trailing mark edge positions can be stored to memory 130 ofthe disc recorder.

When this optical disc is then loaded, area 1603 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the peak and bias power level informationin memory 130 is then obtained. This ratio can then be multiplied withthe specific bias power level obtained by test recording to obtain thespecific peak power setting. Test recording for determining the specificpeak power setting can therefore be omitted, and the time required todetermine the conditions for optimized recording can be shortened.

If the temporary power level information for adjusting the leading andtrailing mark edge positions is not recorded to memory 130, theoperational power level information can be used. First, the operationalpower setting recorded to area 1603 is read. The bias power setting ofthe temporary power level information is then obtained by testrecording, and the ratio between the peak and bias power settings of theoperational power level setting is calculated. The optimum peak powerlevel of the temporary power level information can then be calculated bymultiplying this ratio with the bias power setting of the temporarypower level information. Test recording for determining the specificpeak power setting of the temporary power level can therefore beomitted, and the time required to determine the conditions for optimizedrecording can be shortened.

If information specific to the optical disc 1801, such as the discmanufacturer, product number, production date and location, disc format,and recording film type, is stored to area 1803 of the optical disc 1801shown in FIG. 18 in addition to the adjustment method information, thisdisc-specific information and the operational power level information(such as peak power, bias power, margin constant) used for adjusting theleading and trailing mark edge positions can be stored to memory 130 ofthe disc recorder.

When this optical disc is then loaded, area 1803 is read to detectwhether the disc-specific information is already in memory 130. If itis, test recording is then performed to determine the specific biaspower level. The ratio between the peak and bias power level informationin memory 130 is then obtained. This ratio can then be multiplied withthe specific bias power level obtained by test recording to obtain thespecific peak power setting. Test recording for determining the specificpeak power setting can therefore be omitted, and the time required todetermine the conditions for optimized recording can be shortened.

If the temporary power level information for adjusting the leading andtrailing mark edge positions is not recorded to memory 130, theoperational power level information can be used. First, the operationalpower setting recorded to area 1803 is read. The bias power setting ofthe temporary power level information is then obtained by testrecording, and the ratio between the peak and bias power settings of theoperational power level setting is calculated. The optimum peak powerlevel of the temporary power level information can then be calculated bymultiplying this ratio with the bias power setting of the temporarypower level information. Test recording for determining the specificpeak power setting of the temporary power level can therefore beomitted, and the time required to determine the conditions for optimizedrecording can be shortened.

It is to be noted that the optimum positions of the leading and trailingmark edges are determined in this exemplary embodiment of the presentinvention assuming an ideal reproduction path from the recording mediumto the digitizing circuit. It will be obvious, however, thatreproduction systems with less than ideal performance characteristicsare also possible.

FIG. 26 shows the group delay frequency characteristic of thereproduction system in an actual disc recorder. Although a flat groupdelay to signal frequency characteristic is the ideal, a group delaycharacteristic 2601 that is not flat as shown in FIG. 26 is alsopossible. When the frequency characteristic of the group delaycharacteristic is not constant, edge shifting may occur in signals withmark and space combinations of various lengths. If the first drive pulseposition Tu and last drive pulse position Td are determined in a discrecorder subject to edge shifting, this edge shift component will beincluded in Tu and Td. While this is not particularly a problem when thedisc is then reproduced on the same disc recorder, reproductionperformance will be degraded as a result of edge shifting when the discis read on a disc recorder with a flat group delay characteristic.

FIG. 27 shows the read signal generated by a disc recorder having agroup delay characteristic that is not flat. While the signalrepresented in FIG. 27 is a simple pattern signal with particularly longmarks and spaces, a disc recorder having a non-flat group delaycharacteristic produces a read signal that has a slope even in spacecomponents where the signal should be flat regardless of the shape ofthe mark. The flatness of the group delay characteristic can be detectedby detecting this slope.

FIG. 28(a) shows an exemplary method of detecting signal flatness usinga test signal comprising long spaces. This signal is preferably anembossed pit sequence formed at the inside circumference of therecording medium, but can be, for example, a signal with a constant 14Tspace period used as a frame synchronization signal, a signalprerecorded to a specific area of the disc, or a signal recorded by thedisc recorder. What is important is that the test signal contain longspaces of, for example, 7T to 14T.

Line 2801 in FIG. 28 indicates the slice level of the digitizingcircuit, and curve 2802 is the read signal of a 14T space test signalrecorded to and then reproduced from the disc. Signal 2802 is sampled attimes t0 to t14 based on a PLL clock, obtaining samples s1 to s13.

FIG. 28(b) shows a sampling operator 2803 for processing samples s1 tos13 to obtain a sample value. More specifically, the sampling operator2803 adds samples s1 to s6, and s8 to s13, and then obtains thedifference between the two sums. If the signal 2802 has a wave form asshown in FIG. 28, the output from sampling operator 2803 will be anegative value; if the wave slope is the reverse of that shown in FIG.28, the result will be positive.

It is to be noted that while it is herein assumed that this samplingcircuit and operator are digital circuits, the present invention shallnot be so limited insofar as a slope as shown by curve 2802 is output asa negative (or positive) value, and the opposite slope is output as apositive (or negative) value.

FIGS. 29(a) and (b) show a group delay compensation circuit for a groupdelay with a specific frequency characteristic.

FIG. 29(a) shows an op-amplifier circuit; capacitor 2901 is insertedthrough resistor 2902 to apply a specific frequency characteristic tothe feedback resistance of a normal inverting op-amplifier 2903. Adesirable group delay characteristic in which the high frequency side isdelayed can be achieved by appropriately setting the resistance ofresistor 2902 and the capacitance of capacitor 2901. If it is desirableto delay the low frequency side, capacitor 2901 can be replaced by aninductor.

FIG. 29(b) is a block diagram of an exemplary group delay compensationcircuit. The read signal is delayed by delays 2904 and 2905. Theoriginal signal, the signal delayed by delay 2904, and the signaldelayed by delay 2905 are respectively weighted by weightingcoefficients 2906, 2907, and 2908, and the weighted signals are thenadded by adder 2909. Signal 2802 is the signal shown in FIG. 28(a).Detector 2803 is the operator shown in FIG. 28(b), for example.Controller 2910 outputs a coefficient based on the output value from thedetector 2803 to control the amplification rate of amplifiers 2906,2907, and 2908. After amplification, that is, weighting, by amplifiers2906, 2907, and 2908, the signals are added by adder 2909, therebyassuring a flat group delay characteristic for the signal reproductionsystem, including the group delay compensation circuit.

It is known that if coefficients 2906 and 2908 are equal in thiscircuit, the group delay characteristic will be flat, and that if theyare not equal a frequency characteristic is imparted to the group delay.It is therefore possible by appropriately selecting the coefficients toachieve an equivalent circuit with the desired group delaycharacteristic.

The group delay characteristic of the entire reproduction system canalso be made flat by detecting the flatness of the space component shownin FIG. 28(a) and controlling the group delay compensation shown inFIGS. 29(a) and (b) and inserted somewhere in the reproduction system.By then determining Tu and Td, edge shifting when the disc is reproducedby another disc recorder can be minimized, and greater compatibility canbe achieved for reproducing the disc in different disc recorders.

FIG. 30 shows the jitter in the read signal when the group delaycompensation of the circuit shown in FIG. 29 is changed. It is to benoted that this read signal is preferably obtained from a pit sequenceformed at the inside circumference of the recording medium. However, itcan alternatively be a signal recorded to a specific area of therecording medium by the disc recorder in which Tu and Td are set toprevent edge shifting.

Curve 3001 results from a reproduction system with a flat group delaycharacteristic; curve 3002 when the group delay characteristic is notflat. As noted above, edge shifting occurs when the group delaycharacteristic of the entire reproduction system is not flat. Thisdegrades the read performance, and leads to a higher error rate andjitter. If the group delay characteristic is flat, the error rate andjitter are least as shown by curve 3001 when there is no group delaycompensation applied by the compensation circuit, but jitter increasesas group delay compensation increases.

However, if the disc recorder has a specific group delay characteristicin its reproduction system, jitter will be least when a certain groupdelay compensation is applied. Because there is the least edge shiftingwhen compensation is applied to minimize jitter, it can also beconcluded that the group delay characteristic is substantially flat. Itis therefore possible to minimize edge shifting when a disc recorded onone machine is reproduced on another, and thus assure the greatest readcompatibility, by controlling the group delay compensation so as tominimize jitter as shown in FIG. 29 while detecting jitter in a feedbackloop, and then determine Tu and Td. It will also be obvious to one withordinary skill in the related art that the invention shall not belimited to detecting jitter in this feedback loop, and the error rate orother characteristic that varies with the group delay characteristic andedge shifting can be alternatively used.

It should also be noted that if the specific group delay characteristicof the disc recorder does not change over time, the same effect can beachieved by compensating for the group delay characteristic in thesignal process. Furthermore, if the group delay characteristic is notdevice-dependent and has a specific characteristic, the same effect canbe achieved by compensating for the group delay characteristic using atypical compensation value.

As described above, a recording method for information according to thepresent invention can compensate at the time data is recorded for theeffects of thermal accumulation and thermal interference duringrecording, and thereby record data with little jitter, by determiningbefore data recording the position of the leading edge of each markbased on the length of the mark to be recorded and the length of thepreceding space, and determining the position of the trailing edge ofeach mark based on the length of the mark to be recorded and the lengthof the following space.

It is yet further possible to optimize recording by determining theoptimum laser power settings to be used for test recording before thetest recording operation whereby the above-noted optimum leading andtrailing mark edge positions are determined.

It is yet further possible to further optimize recording by determiningthe optimum laser power settings to be used for data recording afterdetermining the optimum leading and trailing mark edge positions asdescribed above.

Although the present invention has been described in connection with thepreferred embodiments thereof with reference to the accompanyingdrawings, it is to be noted that various changes and modifications willbe apparent to those skilled in the art. Such changes and modificationsare to be understood as included within the scope of the presentinvention as defined by the appended claims, unless they departtherefrom.

1-69. (canceled)
 70. A data recording medium having a plurality ofconcentric or spiral tracks for recording information represented asmarks and spaces between the marks, the marks being formed by emittingto a track recording surface an optical beam modulated by a plurality ofdrive pulses, wherein the drive pulse count is adjusted according to alength of a mark part in the original signal to be recorded to thetrack, said data recording medium comprising: prerecorded control data,said prerecorded control data comprising: timing information includingat least one of first information for determining a rising edge positionof a first pulse of said drive pulses, and second information fordetermining a trailing edge position of a last pulse of said drivepulses; and a test recording area for carrying out a test recording. 71.A data recording medium as claimed in claim 70, wherein said controldata further comprises information for asymmetry as one of saidoperational power information.
 72. A recording and reproducing apparatusfor use in recording data to and reproducing data from a data recordingmedium, the data recording medium having a plurality of concentric orspiral tracks for recording information represented as marks and spacesbetween the marks, the marks being formed by emitting to a trackrecording surface an optical beam modulated by a plurality of drivepulses where the drive pulse count is adjusted according to a length ofa mark part in the original signal to be recorded to the track, the datarecording medium comprising: prerecorded control data, the prerecordedcontrol data comprising: timing information including at least one offirst information for determining a rising edge position of a firstpulse of the drive pulses, and second information for determining atrailing edge position of a last pulse of the drive pulses; and a testrecording area for carrying out a test recording, said recording andreproducing apparatus comprising: a reading system that reads the timinginformation; a determining system that determines drive pulse based onthe timing information; and a testing system that writes and reads atest signal using the test recording area.
 73. A recording andreproducing apparatus as claimed in claim 72, wherein said determiningsystem for determining drive pulse emission power has a random signalgenerator for generating a random signal.
 74. A recording andreproducing apparatus as claimed in claim 72, wherein said determiningsystem for determining drive pulse emission power has a simple patternsignal generator for generating a simple pattern signal that is a signalhaving a single period.
 75. A recording and reproducing method for usein recording data to and reproducing data from a data recording medium,the data recording medium having a plurality of concentric or spiraltracks for recording information represented as marks and spaces betweenthe marks, the marks being formed by emitting to a track recordingsurface an optical beam modulated by a plurality of drive pulses wherethe drive pulse count is adjusted according to a length of a mark partin the original signal to be recorded to the track, the data recordingmedium comprising: prerecorded control data, said prerecorded controldata comprising: timing information including at least one of firstinformation for determining a rising edge position of a first pulse ofsaid drive pulses, and second information for determining a trailingedge position of a last pulse of said drive pulses; and a test recordingarea for carrying out a test recording, said recording and reproducingmethod comprising: reading the timing information; determining drivepulse based on the timing information; and writing and reading a testsignal using the test recording area.
 76. A recording and reproducingmethod as claimed in claim 75, wherein said determining includesgenerating a random signal.
 77. A recording and reproducing method asclaimed in claim 75, wherein said determining includes generating asimple pattern signal that is a signal having a single period.